332 of 9317 documents found     Page 1 of 17
	Title/Size/Author/Abstract
	The Birth of Tape Recording in the U.S. 3866955 bytes (CD aes10)
Author(s): Hammar, Peter
Publication: Preprint 1928; Convention 72; September 1982
Abstract: In 1945, when Major Jack Mullin, U.S.A. Signal Corps, came home to San Francisco with two German Magnetophon audio tape recorders, he had no idea that he and three other Bay Area engineers, Bill Palmer, Harold Lindsay, and Myron Stolaroff · not big companies like GE, RCA or Westinghouse · would be the ones to revolutionize American recording. By 1947, tiny Ampex Corporation surprised U.S. studios and broadcasters with the first successful American version of the tape recorder. How were Ampex's Lindsay and Stolaroff able to build a high-fidelity tape machine while others failed?
	The Multichannel Recording for Mastering Purposes 2637860 bytes (CD aes2)
Author(s): Fujii, Mort; Rehklau, George; McKnight, John; Miltenburg, William
Publication: Volume 8 Number 4 pp. 245·257; September 1960
Abstract: In the past, all master recording was done monophonically on full-track, quarter-inch magnetic tape, but today most master recording is done stereophonically on three-channel half-inch tape. This four-part paper emphasizes the solutions to the problems which are peculiar to three-channel recording and multichannel magnetic recorders. First, the basic technical requirements and differences from single channel recorders are outlined; second, mechanical problems of securing ease of operation and flutter and wow are discussed; third, the signal-to-noise considerations of track width and spacing, and equalization are discussed; and fourth, practical operation of multichannel recorders in a recording studio is described.
	The Frequency Response of Magnetic Recorders for Audio 940159 bytes (CD aes2)
Author(s): McKnight, John G.
Publication: Volume 8 Number 3 pp. 146·153; June 1960
Abstract: The total frequency response of a magnetic tape recorder depends on the amplifier responses, the heads, and the tape. Response standards have been established by NAB and CCIR for the reproduce chain, using an ·ideal· reproduce head and a prescribed post-emphasis. Techniques are discussed and data shown for calibrating the reproduce chain; the ideal reproduce head is physically realizable. The only standard for the record chain is that it must produce tapes which reproduce properly on a standard reproduce chain. Data show that the frequency-dependent response loss of the record chain may be made negligible. A record adjusting tape was chosen, and the required preemphasis derived. Wavelength-dependent losses are appreciable; their causes are briefly discussed and found to be inherent in the tape and record heads used at the present state of the art.
	The Measurement of Medium-Wavelength Flux on a Magnetic Tape Record 1192855 bytes (CD aes8)
Author(s): McKnight, J. G.
Publication: Preprint 654; Convention 36; March 1969
Abstract: Tape flux measurement is useful for standardizing program levels on magnetic tape records, and for measuring the performance of tapes and recording and reproducing heads. A ring-core head is the most satisfactory tape-flux measuring instrument, but calibration of the flux-to-voltage sensitivity is difficult in the general practical case. By using a ·symmetrical head· construction however, the sensitivity is easily calculated and experimentally verified. For practical measurements, a ·high-efficiency head· has the advantage of not changing sensitivity with wear. The flux-efficiency of the core, and the frequency- and wavelength-response factors are all calculated and experimentally verified for both the ·symmetrical· and ·high-efficiency· designs. A flux measurement accuracy of better than 3% is achieved.
	Tape Flux Measurement Theory and Verification 1569510 bytes (CD aes3)
Author(s): McKnight, J. G.
Publication: Volume 18 Number 3 pp. 250·262; May 1970
Abstract: Tape flux measurement is useful for standardizing program levels on magnetic tape records, and for measuring the performance of tapes and recording and reproducing heads. A ring-core head is the most satisfactory tape-flux measuring instrument, but calibration of the flux-to-voltage sensitivity is difficult in the general practical case. By using a ·symmetrical head· construction, however, the average sensitivity of front and rear gaps is accurately calculated quite easily. For practical measurements, a ·high-efficiency head· has the advantage of requiring only one (not two) measurements. The flux-efficiency of the core, and the frequency- and wavelength-response factors are all calculated and experimentally verified for both the symmetrical and the high-efficiency designs. A transfer to unidirectional flux and magnetometer flux measurement gives further verification. A flux measurement accuracy of better than 3% is achieved at medium wavelengths of 0.25 to 2.0 mm.
	Jack Mullin: The Man and His Machines 4440482 bytes (CD aes5)
Author(s): Hammar, Peter
Publication: Volume 37 Number 6 pp. 490·496, 498, 500, 502, 504, 506, 508, 510, 512; May 1989
Abstract: Not available.
	Performance and Reliability Requirements for a Master Tape Recorder 1779888 bytes (CD aes2)
Author(s): Narma, Rein; Fujii, W. M.
Publication: Volume 12 Number 4 pp. 274·279; September 1964
Abstract: In view of the maximum performance and reliability demands of the record industry for tape recorders, the current state of the art is evaluated, and the performance of a new tape recorder is compared to the industry's requirements and to existing tape recorders.
	Some New Data on Frequency Response of Magnetic Recorders for Audio 771945 bytes (CD aes7)
Author(s): McKnight, John G.
Publication: Preprint 96; Convention 11; September 1959
Abstract: The frequency response of a magnetic tape recorder depends on the frequency response and geometric construction of the heads; and on the magnetic and physical properties of the tape. Frequency response standards have been established by NAB and CCIR for the reproduce chain, on the basis of an ·ideal· reproduce head and prescribed post-emphasis. Techniques are discussed and data is shown for calibration of the reproduce chain; the ·ideal· head is seen to be producible in quantity, with care. No standards exist for the record chain, other than that it produces tapes which reproduce properly on a standard reproduce chain. Data shows that the frequency response loss of the record chain is negligible; a record alignment tape has been chosen and data is shown for the required pre-emphasis. Improved tape and heads give more easily realized pre-emphasis curves, and greater high-frequency overload capabilities.
	The Print-Through Phenomenon and Its Practical Consequences 1623137 bytes (CD aes9)
Author(s): Bertram, Neal; Stafford, Michael; Mills, David
Publication: Preprint 1124; Convention 54; April 1976
Abstract: A survey of the existing theory of print-through is presented with a discussion of the implications for the recording engineer. The roles of both the medium and the recording configuration are characterized. Standard print-through measurement methods are compared quantitatively. Advice is presented to the user on how to select and employ tape to insure minimum print-through consistent with other recording objectives.
	Reproducer Test Tapes, Their Evolution and Manufacture 745456 bytes (CD aes7)
Author(s): Morrison, Robert K.
Publication: Preprint 445; Convention 31; September 1966
Abstract: Reproducer Test Tapes (also called ·Alignment Tapes· or ·Standard Tapes·) are used to standardize the azimuth, frequency-response characteristics, and recorded levels of magnetic sound recording systems. Informal ·working standards· and formal standards exist; changes of these standards are discussed, as well as the possible confusion resulting therefrom. The manufacture of Reproducer Test Tapes is discussed, including special requirements for heads and blank tape, and the methods for determining the azimuth and the flux vs. frequency response characteristic. The small errors inherent in a new Test Tape may be greatly increased by accidental damage, and sometimes even in normal usage; handling techniques are described.
	Erasure of Magnetic Tape 1051171 bytes (CD aes2)
Author(s): McKnight, John G.
Publication: Volume 11 Number 3 pp. 223·233; June 1963
Abstract: A brief look is taken at several parameters of the erasing system of a magnetic tape recorder: head losses, remanence vs erasing current, and gap material and size. A re-recording phenomenon is studied, and some measuring problems are discussed.
	Magnetic Head Lapping for Professional Tape Recorders 3072948 bytes (CD aes7)
Author(s): Taber, William D.
Publication: Preprint 539; Convention 33; September 1967
Abstract: Tape head lapping, or resurfacing, has become an important part of the efficient operation of the modern radio station, recording studio and tape duplicating facility, in that it increases the life of the head, allowing it to operate at optimum performance until it is finally worn completely out and must be replaced. The purpose of this paper is to put aside some of the fallacies about head lapping and to point out the advantages as to increased performance and the saving of money.
	Extending Magnetic Head Life by Lapping Techniques 2296736 bytes (CD aes3)
Author(s): Taber, William D.
Publication: Volume 16 Number 1 pp. 61, 62, 64, 66; December 1967
Abstract: Tape head lapping or resurfacing increases the life of heads, allowing them to operate at optimum performance until they are finally worn out completely. Some fallacies concerned with head lapping are disposed of, and the advantages of the procedure are pointed out.
	Reproducer Test Tapes, Their Evolution and Manufacture 723277 bytes (CD aes2)
Author(s): Morrison, Robert K.
Publication: Volume 15 Number 2 pp. 157·162; March 1967
Abstract: Reproducer test tapes (also called alignment tapes or standard tapes) are used to standardize the asimuth, frequency-response characteristics, and recorded levels of magnetic sound recording systems. Informal working standards and formal standards are discussed, with emphasis on changes in standards and possible resulting confusion. The manufacturer of reproducer test tapes is described, including special requirements for heads and blank tape, and the methods for determining the asimuth and the flux vs. frequency response characteristic. Handling techniques which minimize the chance of damage are also described.
	Reducing Distortion in Analog Tape Recorders 1131493 bytes (CD aes3)
Author(s): Griesinger, David
Publication: Volume 23 Number 2 pp. 107·112; February 1975
Abstract: A predistortion system is described which reduces the harmonic and intermodulation distortion of an analog tape recorder by a factor of 10. The system consists of an inexpensive analog computer coupled to a recording head which uses cross-field bias. The system is both accurate and easy to adjust. The cross-field bias, by narrowing the width of the critical regime, ensures that low distortion is maintained through the entire audio band. Since the correction is applied to the recorded flux, tapes can be played with low distortion on any machine. The system has been tested extensively by recording live classical music, and no audible artifacts have been found. Tapes made with the system are clearer and easier to listen to than tapes made on conventional machines.
	Erasure of Magnetic Tape 766757 bytes (CD aes7)
Author(s): McKnight, John G.
Publication: Preprint 243; Convention 14; September 1962
Abstract: A brief look is taken at several parameters of the erasing system of a magnetic tape recorder: head losses, remanence vs erasing current, and gap material and size. A re-recording phenomenon is studied, and some measuring problems are discussed.
	Tape Flux Measurement Revisited 1479466 bytes (CD aes18)
Author(s): McKnight, John G. (Jay); Cortez, Benito E.; McKnight, Jeffrey A.
Publication: Volume 46 Number 10 pp. 845·858; September 1998
Abstract: Analog magnetic recording standards specify the recorded signal magnitude in terms of short-circuit flux per unit track width, called fluxivity. Two flux measurement methods are standardized: a direct ac method using a high-efficiency head (AES7/ANSI S4.6) and a transfer-to-dc method using a fluxmeter (German standard DIN 45 520). A transfer-to-dc measurement made in the 1950s is used to calibrate the fluxivity of German calibration tapes. When these tapes are measured by the direct ac method, the fluxivity is 10% less than the stated value. Thus the 1950s German transfer-to-dc measurement was 10% more sensitive than the direct ac measurement. A new comparison of the two measurement methods shows that they actually have the same sensitivity; the experimental error of our measurements is about ±1%. Thus we conclude that the German measurement in the 1950s must have had a 10% error, and that the fluxivity on all of the calibration tapes based on the old German measurement is 10% less than the stated value·tapes identified as 320 nWb/m are actually 288 nWb/m.
	Magnetic Recording for Original Recordings 741334 bytes (CD aes3)
Author(s): Mullin, John T.
Publication: Volume 25 Number 10/11 pp. 696·701; September 1977
Abstract: Why did it take half a century from the time Valdemar Poulsen applied for a patent on his magnetic recording device for it to become the most important tool in the sound recording industry? This paper reviews the history of this development and dwells for a time on how and why it is the focal point in the everyday operation of the recording studio.
	Speed, Pitch and Timing Errors in Tape Recording and Reproducing 1047004 bytes (CD aes3)
Author(s): McKnight, John G.
Publication: Volume 16 Number 3 pp. 266·274; June 1968
Abstract: Because tape is a plastic medium driven by a capstan in a complicated rolling process, an accurate specification of ·tape speed· is not simple. However, it is shown that even a complete specification of tape speed alone is not adequate to specify the pitch and timing error because changes of the recorded wavelength due to tape length changes cause additional independent timing and pitch errors of up to 1.0%. These are significant in comparison with the NAB tape speed tolerance of ±0.2%. Measurement techniques are also reviewed.
	A New Equalization Characteristic for Master Tape Recording 561883 bytes (CD aes2)
Author(s): Goldberg, A. A.; Torick, Emil L.
Publication: Volume 8 Number 1 pp. 29·34; December 1959
Abstract: Although the signal-to-noise ratio of master tape recorders is good by present standards, a low level background noise still exists. This is heard as hiss, due to the characteristic of the ear. Hiss reduction is accomplished by a new equalization that increass the tape loading in the frequencies between 1000 and 15,000 cps and decreases the hiss by 6 db as compared with NAB equalization. This is achieved at the expense of increased distortion within the hiss frequencies.

	332 of 9317 documents found     Page 2 of 17
	Title/Size/Author/Abstract
	Reliability Testing of R-DAT Tapes Subjected to Mechanical and Environmental Stress 1636879 bytes (CD aes12)
Author(s): Popovic, Slobodan
Publication: Preprint 3442; Convention 93; September 1992
Abstract: The purpose of this study was to examine the reliability of R-DAT recording media with respect to frequent usage and exposure to extreme environmental conditions during storage. Four brands of R-DAT tapes were subjected to mechanical stress, environmental stress, and a combination of both. Data generated from these tests was analyzed objectively, subjectively evaluated, and subsequently compared. The stability of the media was objectively verified following one year of storage and further mechanical stress exposure.
	Absolute Flux and Frequency Response Characteristics in Magnetic Recording: Measurements, Definitions, and Standardization 2146111 bytes (CD aes2)
Author(s): McKnight, John G.
Publication: Volume 15 Number 3 pp. 254·272; June 1967
Abstract: In order to have interchangeable tape recordings, standards are needed for frequency response characteristics and for the absolute value of the recorded flux. It is shown that the recorded signal is best measured and specified as the ·shortcircuit flux per unit track width·; and measurement techniques are reviewed. The need for equalization, and the division into recording and reproducing equalization, are developed. Standard equalizations of many organizations are shown as flux characteristics. Standard reference fluxes and operating levels are tabulated and discussed. The terms necessary for response and level standardization are proposed and defined, and, since terms are not defined in presently published standards, those defined here are compared with usages of the standards.
	Mechanical Damping in Tape Transports 760094 bytes (CD aes2)
Author(s): McKnight, John G.
Publication: Volume 12 Number 2 pp. 140·146; March 1964
Abstract: Most of the dynamic elements of a tape transport store energy rather than dissipate it; therefore distrubances due to mechanical imperfections will result in the undesirable condition of oscillations of speed which die out slowly. The various physical mechanisms unable for dissipating (damping) this energy are shown along with a quantitative analysis (using electrical analogs) of their effects.
	Speed, Pitch, and Timing Errors in Tape Recording and Reproducing 762015 bytes (CD aes7)
Author(s): McKnight, John G.
Publication: Preprint 555; Convention 33; September 1967
Abstract: Because tape is a plastic medium driven by a capstan in a complicated rolling process, an accurate specification of ·tape speed· is not simple. However, even a complete specification of ·tape speed· alone is not adequate to specify the pitch and timing error because changes of the recorded wavelength due to tape length changes cause additional independent timing and pitch errors of up to 1.0%. These are comparable to the NAB ·tape speed· alone is not adequate to specify the pitch and timing error because changes of the recorded wavelength due to tape length changes cause additional independent timing and pitch errors of up to 1.0%. These are comparable to the NAB ·tape speed· tolerance of ±0.2%. Measurement techniques are also reviewed.
	Tape Flux Measurement Revisited 1926251 bytes (CD aes14)
Author(s): McKnight, John G. (Jay); Cortez, Benito E.; McKnight, Jeffrey A.
Publication: Preprint 4802; Convention 105; August 1998
Abstract: Analog magnetic recording standards specify recorded signal magnitude in terms of short-circuit flux per unit track width, called fluxivity. Two flux measurement methods are standardized: a direct ac method using a high-efficiency head (AES7/ANSI Standard S4.6); and a transfer-to-dc method using a fluxmeter (German Standard DIN 45 520). A transfer-to-dc measurement made in the 1950s is used to calibrate the fluxivity of German calibration tapes. When these tapes are measured by the direct ac method, the fluxivity is 10% less than the stated value. Thus the 1950s German transfer-to-dc measurement was 10% more sensitive than the direct ac measurement. A new comparison of the two measurement methods shows that they actually have the same sensitivity within an experimental error of about 0.5%. Thus we conclude that the German measurement in the 1950s must have had a 10% error, and that the fluxivity on all of the calibration tapes based on the old German measurement is 10% less than the stated value tapes identified as 320 nWb/m are actually 288 nWb/m.
	Operating Levels in the Duplication of Philips Cassette Records 208587 bytes (CD aes2)
Author(s): McKnight, John G.
Publication: Volume 15 Number 4 pp. 454, 456; September 1967
Abstract: Not available.
	An Overview of the Recording Techniques and Equipment for Post Production 665824 bytes (CD aes9)
Author(s): Keiser, Samuel L.
Publication: Preprint 1338; Convention 59; January 1978
Abstract: Once one takes the step to a separate audio recorder, time-code locked to the video recorder, production flexibility is limited only by one's imagination. This paper will review those features of today's audio recorders which are of significance to television production. Included in the paper is a discussion of advantages such as audio signal quality, audio material handling techniques, and cost-time savings, as well as limitations that must be considered in operation of the audio recorder.
	Special Reproduce System for the Independence Hall at Knott's Berry Farm 2124922 bytes (CD aes7)
Author(s): Hosoda, Akio John
Publication: Preprint 541; Convention 33; September 1967
Abstract: On July 4, 1966, Knott's Berry Farm, a favorite amusement center in southern California, dedicated the latest addition to their facilities, a reconstruction of Independence Hall in Philadelphia. To add realism, the Special Products Department of Ampex Corporation designed and built a special audio system to recreate the historic events surrounding the signing of the Declaration of Independence which took place 190 years ago.
	A Digital Audio Recorder Format for Professional Applications 528249 bytes (CD aes9)
Author(s): Engberg, Edwin W.
Publication: Preprint 1413; Convention 61; October 1978
Abstract: In anticipation of the emergence of Digital Audio Recorders, I have been conducting a program to investigate the applicability of various electrical and mechanical recording formats to the professional audio community. Operational features have been defined that a professional digital audio recorder must have to fulfill the needs of current recording techniques as well as new ones which will evolve because of the capabilities of digital recording. This paper presents a digital audio recorder format which provides these operational features.
	Use of Capstan Servo Systems in Audio Recorders for Multimedia Synchronization 2539473 bytes (CD aes8)
Author(s): Cartalano, Louis J.; Langevin, Robert Z.
Publication: Preprint 892; Convention 43; August 1972
Abstract: The versatility of a dc capstan servo simplifies synchronization of audio recorders to each other, to video tape recorders or to sprocketed film equipment. Several systems will be described, including pilot tone resolving, video lock and film lock, all of which use pulse counting techniques. A system which uses an address code can offer further advantages. The SMPTE code and how one system uses it to synchronize as many as six tape transports will be described.
	The 120-ips Tape Duplicator for Four-Track Commercial Stereo Tapes 1751532 bytes (CD aes2)
Author(s): Isberg, R. A.
Publication: Volume 8 Number 2 pp. 105·110; March 1960
Abstract: Improvement in tape reproduce heads, now record equalization techniques, and tape have brought about the introduction of four-track stereophonic tapes for entertainment uses. The cost of the production of these tapes has been reduced by the savings in the amount of tape requried for a given length of recording and by improvements in tape duplicating equipment. The Ampex S-3300B tape duplicator has been designed particularly for the production of 7-1/2 and 3-3/4-ips four track stereo tapes. The master reproducer operates at either 120 or 60 ips and the slaves operate at 60, 30, or 15 ips. the duplicating speed is twice as fast as that of previous models of Ampex tape duplicators. The 15-ips four-track master tapes required for this system are 1/2 in. wide with AME record characteristics. Record pre-emphasis circuits are provided to suit master to slave speed ratios of 120:60, 60:30, and 60:15 ips.
	The Frequency Spectra of Several Languages as a Criterion for the Frequency Response of Language Laboratories 346291 bytes (CD aes7)
Author(s): McKnight, John G.
Publication: Preprint 288; Convention 15; September 1963
Abstract: The speech of eleven speakers of six languages was measured for peak energy in one-third octave bands, as compared to a reference level established by a vu meter. Levels as high as 0 dB at 10 kc, and -18 dB at 15 kc, were found. A tape speed of at least 7.5 ips is necessary to record all of the speakers without bandwidth restrictions, or level reduction.
	A New Equalization Characteristic for Master Tape Recording 617217 bytes (CD aes7)
Author(s): Goldberg, A. A.; Torick, Emil L.
Publication: Preprint 115; Convention 11; September 1959
Abstract: Master tape recorders, running at 15 inches per second and using NAB equalization, are capable of providing a 55 db signal to noise ratio (peak record level to unweighted noise). Existing disc recording techniques had improved to a point where the audible master tape hiss became objectionable, especially during low level program material. An investigation of this problem resulted in a new equalization that reduces the hiss by 6 db. This work was done prior to the disclosure of the Ampex Master Equalization (AME).* It is gratifying to note the agreement in broad areas between Ampex and CBS data.
	Development of a Low-Flutter Measurement Tape 1309689 bytes (CD aes5)
Author(s): Cross, Lowell
Publication: Volume 45 Number 12 pp. 1067·1081; November 1997
Abstract: Flutter measurement tapes sold to the professional community may contain residual levels of time-base errors that are too high to permit accurate measurements. This study presents a technique for recording tapes with very low residual flutter. A recorder with atransport xervo system was used to make high-speed recordings for measurements as standard speeds. The recorder has low inherent flutter, exceeding the manufacturer's specifications. The high-speed technique reveals that a significant improvement in the recording of flutter measurement tapes is possible, especially when the method is compared to the common procedure of recording at the playback velocity.
	Magnetic Recording Tape: The Influence of the Magnetic Coating Thickness Upon Signal Parameters 1157224 bytes (CD aes3)
Author(s): Manly, Jr., William A.
Publication: Volume 17 Number 2 pp. 178·180, 182, 184, 186, 188, 190, 192, 192B; March 1969
Abstract: An empirical study has been made of the dependence on the thickness of the magnetic coating of bias, sensitivity, response, output at saturation, distortion, print-through, and noise. It is shown that for audio and instrumentation (analog) tapes, where the record head gap is sufficiently long, the greatest percentage of the variations observed in measured parameters is due to the variation in the thickness of the magnetic coatings. In some cases, requirements are such that specification limits require resolutions in coating thickness measurements which are almost unobtainable.
	Tape Reproducer Response Measurements with a Reproducer Test Tape 567886 bytes (CD aes2)
Author(s): McKnight, John G.
Publication: Volume 15 Number 2 pp. 152·156; March 1967
Abstract: The reproducer test tape affords the most satisfactory field means of standardizing magnetic sound recording systems. This method is nevertheless susceptible to numerous errors of measurement due to inappropriate test tape (wrong speed, equalization, track format, or test frequencies), and mechanical misadjustment of the reproducer (head height; asimuth and zenith adjustment; and poor tape-to-head contact due to dirt on heads, inadequate tape tension or wrap around the heads, improper vertex adjustment, worn heads, and improper tape guiding). These errors are described in order that they may be avoided.
	Noise Limitations in Tape Reproducers 1470780 bytes (CD aes2)
Author(s): Skov, Erling P.
Publication: Volume 12 Number 4 pp. 280·293; September 1964
Abstract: Thermal noise, shot noise, 1/f noise, induced grid noise and Barkhausen nise are described and quantitative examples are given. Expressions for thermal noise in mixed resistive and reactive circuits are derived. The relationship between head thermal noise and amplifier shot noise is discussed and measured data are given. The question of tubes vs transistors is touched upon with respect to noise and overload capabilities. The relationship between the noise index of a resistor and the crossover frequency between thermal and 1/f noise is calculated and displayed as a family of curves, and examples are given. Signal-to-noise measurement data from the Ampex MR-70 master recorder are given along with a brief description of the basic design philosophy with respect to noise reduction.
	A Transistorized Amplifier for a Condenser Microphone 893843 bytes (CD aes2)
Author(s): Nakamura, Jinichiro; Wakabayashi, Rinske
Publication: Volume 15 Number 2 pp. 200, 202, 204, 206, 208, 210, 214, 216; March 1967
Abstract: The commercial availability of field effect transistors (FET) made it possible to design a transistorized amplifier for a condenser microphone which takes advantage of the FET's high input impedance and low noise combined with gain stability vs temperature changes. The correlation between circuit constants and the noise generated in the FET and in the next stage is explored by means of a suitable manipulation of the equivalent circuit representation of the preamplifier. Experimental results show that the insertion of a fairly large resistor between the source and the gate of the FET results in a good signal-to-noise ratio.
	A Flexible Sheet Magnetic Recorder 831861 bytes (CD aes7)
Author(s): Skov, Erling
Publication: Preprint 421; Convention 17; September 1965
Abstract: This paper describes the design considerations and final performance specifications of the Cue-Matic Recorder*, a record/reproduce system which was developed to enable broadcasters to play short (3 minutes, 45 seconds), early generation program material directly on the air. The recording medium is a 3-mil-thick, circular magnetic sheet. The record/reproduce machine cues the sheet automatically and provides instant start and automatic stop.
	Dynamic Range Limitations in Tape Recording 484304 bytes (CD aes2)
Author(s): Langevin, Robert Z.
Publication: Volume 12 Number 4 pp. 294·297; September 1964
Abstract: Limitations are imposed on the dynamic range of a tape recording by the type of tape, track width and tape speed. Dynamic range will increase as tape speed decreases, and as track width decreases; the style of tape will also control dynamic range. Equipment can limit the maximum signal by adding amplifier distortion, by incorrect bias, or by introducing even-order distortion from magnetized heads or unsymmetrical bias. Misalignment of track height between recording and reproducing heads can degrade the dynamic range. The common noise contributors are: dc noise from magnetized heads or unsymmetrical bias; noise caused by too low a bias frequency; modulation noise (both AM and FM), and reproducing head and amplifier noise. It is, however, perfectly feasible to build a recorder that poses no practical limitation to dynamic range. Even with low-noise tapes and narrow track widths, the noise is limited by the tape itself.

	332 of 9317 documents found     Page 3 of 17
	Title/Size/Author/Abstract
	The Distribution of Peak Energy in Recorded Music and Its Relation to Magnetic Recording Systems 1194179 bytes (CD aes2)
Author(s): McKnight, John G.
Publication: Volume 7 Number 2 pp. 65·71, 80; March 1959
Abstract: Data is needed on the distribution of peak energy in music in order to design preemphasis on the basis of equal probability of overload at all frequencies. Previously published data is discussed, and new data is presented and discussed. The data show that energy distribution is very variable; the energy may be within plus or minus 3 db from 40 c to 16 kc; or the energy may be down as much as 30 db at 40 c and 6 kc.
	Signal-To-Noise Problems and A New Equalization for Magnetic Recording of Music 883552 bytes (CD aes2)
Author(s): McKnight, John G.
Publication: Volume 7 Number 1 pp. 5·12; December 1958
Abstract: Measuring procedures and specifications currently used in the sound recording industry are inadequate. A weighting network should be used to objective noise measurement work to evaluate developments toward a lower noise system. We know that the ear is most sensitive in the 1 to 6 kc region, and it is possible to use preemphasis in this region. Better signal-to-noise ratio may be obtained in 15 ips magnetic recorders by utilizing fully their present capabilities. Subjective listening tests show that a system with the 1 to 6 kc region pre-emphasized (the AME curve) is some 7 db quieter than the same system using the NAB curve, but does not show any audible increase in distortion.
	Azimuth and Interchannel Time Displacement Error in Multi-Track Magnetic Tape Recording 873610 bytes (CD aes9)
Author(s): McKnight, John G.
Publication: Preprint 1666; Convention 66; April 1980
Abstract: Tape is often slit with a sinuous centerline ("country laning"). When this tape travels through a transport, the recording on one track shows a varying time displacement with respect to that on another track. When the same signal is recorded on two tracks, and the reproduced signals are subsequently combined, the time displacement produces a "comb filter" frequency response. The output of a full-track head shows a response which is similar up to the first output null. This filter response is used here as a "slope detector" to measure the short-term time azimuth angle variations. Typical peak to peak azimuth angle variations are 600 microradians (0.03 degrees, or 2 minutes); this sets a limit to the interchannel time-displacement performance of recording systems, and to the accuracy of azimuth angle measurements.
	Polarity and Phase Standards for Analog Tape Recorders 964829 bytes (CD aes10)
Author(s): Vanderkooy, John; Lipshitz, Stanley P.
Publication: Preprint 1795; Convention 69; April 1981
Abstract: Under suitable conditions, reversing the polarity of an audio signal produces an audible but subtle effect. We propose a polarity standard for analog tape recorders and reproducers in the face of several other proposals which are subject to misinterpretation or are used solely as in-house standards. The physical principles of the reproduction process are discussed to clarify the presentation and implementation of our proposed polarity standard.
	An Audio/Video Simulation Facility 557215 bytes (CD aes10)
Author(s): James, David V.
Publication: Preprint 1768; Convention 69; April 1981
Abstract: The digital audio/video simulation facility was constructed to aid in the development of new signal processing algorithms. A new general purpose PDP-11/55 computer is used to process data in non-real-time, but real-time evaluation of the results is supported. Software development was minimized by using the same signal processing modules for one dimensional (audio) and two dimensional (video) signal processing. All programs are well written in a higher level language (C) and can be transported to other computers using the UNIX operating system. The audio portion of the facility supports real time input/output of stereo audio channels at a 50kHz sampling rate. Interactive experiments involving A/B comparisons are available for evaluation of new algorithms. A tape recording illustrates the usefulness of the system.
	The Big Sound Is On The Move With Disney On Parade 1421006 bytes (CD aes8)
Author(s): Huff, Albert A.; Blanton, William E.
Publication: Preprint 716; Convention 38; April 1970
Abstract: Disney on Parade, a NAWAL Production, is the newest attraction to be designed specifically for the arena show market. The attraction travels once a week from arena to arena in fifteen semi trucks and trailers. There are three and one half trucks of wardrobe, seven trucks of scenery and props, and two trucks of lighting equipment. But that is not all: there is one truck load of sound equipment. This paper will describe this unique road show sound system.
	The Design of a High-Performance Tape Duplicating System 1502171 bytes (CD aes8)
Author(s): Hille, Peter F.
Publication: Preprint 692; Convention 37; September 1969
Abstract: The explosive growth of the prerecorded tape market has placed unprecedented production burdens on manufacturers of music-on-tape. The techniques used to produce reel-to-reel copies in moderate quantities are simply inadequate for high-volume duplication to the casssette and cartridge formats. The combination of production requirements and the critical nature of narrow track, short wavelength copies has created the need for a new generation of tape duplicating equipment, which is the subject of this paper.
	Magnetic Recording Tape: The Influence of the Magnetic Coating Thickness Upon Signal Parameters 1220984 bytes (CD aes7)
Author(s): Manly, Jr., William A.
Publication: Preprint 614; Convention 35; September 1968
Abstract: An empirical study has been made on the dependence of bias, sensitivity, response, output at saturation, distortion, print through, and noise, on the thickness of the magnetic coating. It is shown that for audio and instrumentation (analog) tapes, where the record head gap is sufficiently long, the greatest percentage of the variations observed in measured parameters is due to the variation in the thickness of the magnetic coatings. In some cases, the customer requirements are such that specification limits require resolutions in coating thickness measurements which are almost unobtainable.
	Tape Reproducer Response Measurements with a Reproducer Test Tape 562993 bytes (CD aes7)
Author(s): McKnight, John G.
Publication: Preprint 446; Convention 31; September 1966
Abstract: The Reproducer Test Tape affords the most satisfactory field means of standardizing magnetic sound recording systems. This method is nevertheless susceptible to numerous errors of measurement due to: 1) inappropriate Test Tape (wrong speed, equalization, track format, or test frequencies), and 2) mechanical misadjustment of the reproducer (head height; azimuth and zenith adjustment; and poor tape-to-head contact due to ·dirt· on heads, inadequate tape tension or wrap around the heads, improper vertex adjustment, worn heads, and improper tape guiding).
	Signal-to-Noise Problems and a New Equalization for Magnetic Recording of Music 985790 bytes (CD aes7)
Author(s): McKnight, John G.
Publication: Preprint 58; Convention 10; August 1958
Abstract: General problems in defining and measuring signal to noise ratio for high quality music recording, and an improvement in the subjective signal to noise ratio of the magnetic recorder obtained with a new equalization. There will be a demonstration on the new AME equalization.
	Pre- and Postemphasis Techniques as Applied to Audio Recording Systems 1090807 bytes (CD aes4)
Author(s): Fielder, Louis D.
Publication: Volume 33 Number 9 pp. 649·658; August 1985
Abstract: Audio recorders benefit from pre- and postemphasis, which reshapes the noise spectrum to match human audibility thresholds. A 10-dB increase in apparent dynamic range is realized for some digital audio systems. A first-order boost based on the CCITT J.17 preemphasis standard is shown to be appropriate for dynamic range expansion. A survey of peak acoustic levels present in 36 music performances is also included.
	The Print-Through Phenomenon 1889831 bytes (CD aes4)
Author(s): Bertram, H. Neal; Stafford, Michael K.; Mills, David R.
Publication: Volume 28 Number 10 pp. 690·705; September 1980
Abstract: A survey of the existing theory of print-through is presented. The roles of both the medium and the recording configuration are characterized. A quantitative expression is given for the comparison of print-through measurements by the variaous standard techniques. Advice is presented to the user on how to select and employ tape to ensure minimum print-through, consistent with other recording objectives.
	Transportable Sound Amplification for Disney on Parade 1283394 bytes (CD aes3)
Author(s): Huff, Albert A.; Blanton, William E.
Publication: Volume 19 Number 8 pp. 669·673; August 1971
Abstract: This paper describes the unique design requirements for reproducing 65 inputs using a combination of both live pick-up and prerecorded tape for the Disney On Parade show. Also described are the massive portable speaker systems and the all weather mobile trailer containing a unique control console, a multitude of equipment racks with an audio output of over 1-KW, and instrumentation which provides for individual arena equalization.
	Sound Activity of the California Gray Whale, Eschrichtius Glaucus 482129 bytes (CD aes2)
Author(s): Eberhardt, Robert L.; Evans, William
Publication: Volume 10 Number 4 pp. 324·328; September 1962
Abstract: Early in 1962, the behavior of the gray whale (Eschrichtius glaucus) was observed on its calving grounds in Baja California del Sur, Mexico. At the same time the Pacific bottle-nosed dolphin (Tursiops gulli) was also seen. Sounds made by both species were recorded with an AN/PQM-A1 Noise Measuring Set and Ampex 351, 2-Channel Tape Recorder. The frequency response of this equipment was from 40 to 20,000 cps ±2 db. Within this range the gray's sounds were heard from the lower limit up to 700 cps, with the greatest concentration of energy from 80 to 300 cps. Pulses lasted for 0.10 sec on the average and occurred in groups of 4 to 6. Tursiops were heads to echolocate with their characteristic ·clicks· and to whistle. It is not likely that the gray whale uses echo-location with the same well-defined precision as the bottle-nosed dolphin.
	Master Recording on Two Inch Wide Tape 3398522 bytes (CD aes7)
Author(s): Harshberger, Jr., Robert P.
Publication: Preprint 583; Convention 34; March 1968
Abstract: The use of multitrack master recording has been with us for some time now. Three and four tracks on half inch tape is commonplace. More recently, eight and twelve tracks have been employed on one inch wide tape. This article deals with sixteen and twenty-four trakc master recording on two inch wide tape. Such a system with its large number of separate channels has become necessary due to the modern recording techniques employing many special effects, i.e. echo, reverberation, sound on sound, etc. Older four track and even eight track systems for not offer the flexibility required by many of the present day artists.
	The Effect of Bias Amplitude on Output at Very Short Wavelengths 481519 bytes (CD aes2)
Author(s): McKnight, John G.
Publication: Volume 9 Number 2 pp. 98·102; March 1961
Abstract: In recording with a standard ring head the output is a function of the bias amplitude. The bias necessary for long wavelengths produces severe losses at very short wavelengths. Data are shown for these relationships, for 30 to 0.12 mil wavelengths.
	The Jack Mullin/Bill Palmer Tape Restoration Project 1066675 bytes (CD aes18)
Author(s): Hess, Richard L.
Publication: Volume 49 Number 7/8 pp. 671-674; June 2001
Abstract: Not available.
	Economics of Stereo TV Production Relative to the Creation of Commercials 141903 bytes (CD aes16)
Author(s): Allen, Murray R.
Publication: Paper 4-026; Conference: The AES 4th International Conference: Stereo Audio Technology for Television and Video; April 1986
Abstract: The studio should fit the demands of your situation. There is no reason to have a studio equipped to do more than necessary. We at Universal have twelve studios involved with recording stereo television material.
	Gap-Length Response in Magnetic Reproducers: Calculation, Measurement, and Compensations 570688 bytes (CD aes9)
Author(s): McKnight, John G.
Publication: Preprint 1297; Convention 58; October 1977
Abstract: Gap-length response S(x) is approximated within 1% by S(x) = sin pi x/pi x, where x = 1.1 lg/lambda, lg = mechanical (optical) gap length, lambda = wavelength, and x < 0.5. Alternately, the gap length is calculated from the measured null frequency fn at the speed v; then lg = 0.8795 v/f. Gap-length response compensation is required by standards, but often neglected in practical professional reproducers. Compensation is easily achieved with an RLC ·peaking· circuit.
	Development of a Subjective Flutter Measurement Standard 1041722 bytes (CD aes8)
Author(s): McKnight, John G.
Publication: Preprint 790; Convention 40; March 1971
Abstract: This paper presents the history and the text of a new draft Subjective Flutter measurement standard being considered by IEEE as a replacement for the present ·Flutter Content· standard (IEEE No. 193, ANSI Z57.1-1954). The Subjective Flutter measurement method is identical to the ·weighted quasi-peak· method previously standardized by DIN (45 507, 1966) and CCIR (409-1, 1966), and now under consideration by IEC.

	332 of 9317 documents found     Page 4 of 17
	Title/Size/Author/Abstract
	The Design of a Portable Professional Recorder 3311374 bytes (CD aes7)
Author(s): Rehklau, George; Wilkins, Charles A.; Bennett, John H.
Publication: Preprint 172; Convention 12; September 1960
Abstract: Designing a truly portable magnetic tape recorder for professional use presents problems not enountered in conventional equipment. The mechanical requirements for such a recorder are discussed, and the practical attainment of a small but extremely rugged tape system is described.
	The Effect of Bias Amplitude on Response at Very Short Wavelengths 336224 bytes (CD aes7)
Author(s): McKnight, John G.
Publication: Preprint 171; Convention 12; September 1960
Abstract: In recording with a standard ring head, the output is a function of the bias amplitude. The necessary bias for long wavelengths produces severe losses at very short wavelengths. Data are shown for these relationships, for 30 to 0.12 mil wavelengths.
	Excess Spacing Loss with Alfenol-Core and Ferrite-Core Magnetic Tape Reproducing Heads 642948 bytes (CD aes5)
Author(s): McKnight, John G. (Jay)
Publication: Volume 42 Number 3 pp. 141·146; February 1994
Abstract: The head core material Alfenol (also called Vacodur) is long wearing, but produces an excess spacing loss, apparently dueto a nonmagnetic surface layer of about 0.4 µm that cannot be removed. Ferrite cores sometimes have gap erosion that also causes excess spacing. Because of this, heads with these core materials are not suitable for fundamental measurements. For ordinary sound recording purposes the excess spacing loss is easily compensated when the reproducer response is adjusted by playing a calibration tape.
	Restoration of Kinetophone Sound Motion Pictures 3500530 bytes (CD aes4)
Author(s): Shifrin, Arthur
Publication: Volume 31 Number 11 pp. 874, 876, 878, 880, 882, 884, 886, 888-890; October 1983
Abstract: Introduction by Russ Hamm: Many of you may remember Art Shifrin's talk here in May 1982. At that time he discussed the first sound picture sync system, the Kinetophone (used by Thomas Edison as early as 1913), and how he transferred recordings made on the Edison brown wax cylinders and early disks. That was before he synchronized Kinetophone audio with video. The following presentation brings us up to date on his work during the past year. He will show sound and film demonstrations to illustrate his points. I wish to thank Cameramart for furnishing us with a Sony video projection system and a sync generator; Gotham Audio for providing the noise reduction equipment; and WQXR for the use of their auditorium and staff. Doc Masoomian, and Maurice Dicker, who is running the audio. I also would like to express my appreciation to Ampex for supplying a VPR 80 and TBC 80 to its staff, Dave Bancroft, who will run the videotape machine and Monte Barrie, who helped with the set up.
	Magnetic Design Theory for Tape Recorder Heads 1389975 bytes (CD aes4)
Author(s): McKnight, John G.
Publication: Volume 27 Number 3 pp. 106·120; February 1979
Abstract: The circuit models, formulas, and a computer program in BASIC language are given for calculating the efficiency, frequency response, and complex impedance of a magnetic recording or reproducing head. The model and the calculations take into account the effects of the complex permeability of the elements: a core of nonhomogeneous laminations of specified thickness and geometry; a front gap with nonconducting or conducting gap spacer; gap stray permeance; and a read gap. Measurements presented on eight different heads prove the model and the calculations.
	Low-Frequency Response Calibration of a Multitrack Magnetic Tape Recording and Reproducing System 720174 bytes (CD aes4)
Author(s): McKnight, John G.
Publication: Volume 26 Number 4 pp. 202·208; March 1978
Abstract: Several practical problems make the use of the usual reproducer calibration test tape unsatisfactory below 1000 Hz at a tape speed of 380 mm/s. First, the low frequency equalization standards below 50 Hz are often not followed in practice. Second, there are many different multitrack formats, and this makes a true multitrack reproducer calibration tape commercially infeasible, but although one can calculate a fringing compensation, it is not accurate at the lowest frequencies. Third, the reproducer response inherently undulates, but there are not enough test frequencies to characterize that response. At long wavelengths (low frequencies) the recorded flux is directly proportional to the recording current. Therefore system calibration is best performed by the following method: standardize the recording response (recording head current versus frequency); use recording and reproducing heads of the same core width throughout the system; record a slowly swept-frequency test signal; and adjust the reproducer low-frequency equalizer for flattest overall response.
	Mass Production of Prerecorded Tapes 4148461 bytes (CD aes3)
Author(s): Everett, Thomas D.
Publication: Volume 17 Number 2 pp. 165-170; March 1969
Abstract: This article is concerned with ways and means of utilizing the research and development in audio engineering for the consumer's benefit: the design and implementation of manufacturing facilities to employ the best developments in prerecorded music at reasonable costs, quality and delivery. Although no ultimate in manufacturing techniques are described here, the approaches describe some common elements in mass-production requirements.
	A Preliminary Experiment on the Perceptual Basis for Musical Instrument Families 482299 bytes (CD aes2)
Author(s): Clark, Jr., Melville; Robertson, Paul T.; Luce, David
Publication: Volume 12 Number 3 pp. 199·203; June 1964
Abstract: Experimental evidence is presented for the existence of perceptual families of instruments. This evidence is the result of confusions in identifying the instruments that produced tones when these tones were played back at speeds higher than that at which they were recorded. The string family consists of violins, violas, cellos, and double basses. The brass family consists of trumpets, trombones, tubas, and French horns. The double reed family consists of oboes, English horns, and bassoons, with the bassoons only very weakly linked to the other members of its family. The families are listed in order of decreasing tightness. Very tight subfamilies are formed of the following pairs; violin-viola, cello-double bass, oboe-English horn, trumpet-trombone.
	Time Base Distortion in Continuous Recording Systems: Its Terminology, Measurement, Causes and Effects 677466 bytes (CD aes2)
Author(s): McKnight, John G.
Publication: Volume 10 Number 1 pp. 44·48; December 1961
Abstract: Speed variations of the medium in a recording/reproducing system cause time base distortion (TBD) which is seen as frequency modulation, commonly called ·flutter,· or as changes of time intervals, called ·time displacement error.· Presently used terminology is ambiguous; clarifications and new terminology are proposed. The ultimate use for the system determines which effects of the TBD are of importance: The effects and their measurement in sound recorders and in instrumentation recorders are discussed. Measurements to compare TBD by standard methods are described, and found not to be closely related to either the causes or the effects of the TBD. The speed variations may be determined and analyzed in designing a transport by measuring and analyzing the frequency modulation produced thereby.
	Stereophonic Sound for the Videotape Recorder 1129738 bytes (CD aes2)
Author(s): Snyder, Ross H.
Publication: Volume 7 Number 4 pp. 213·216; September 1959
Abstract: The videotape recorder, now the American standard machine for local clock-time rectification of network programs, required the addition of stereophonic record and playback facilities when AM-TV stereo broadcasting began in the fall of 1958. The manner in which this was accomplished is described, and the performance attainments revealed.
	The Noise in Magnetic Recording Which Is a Function of Tape Characteristics 780001 bytes (CD aes2)
Author(s): Smaller, Philip
Publication: Volume 7 Number 4 pp. 196·202; September 1959
Abstract: A signal which is recorded on magnetic tape undergoes a change in amplitude and frequency before it appears at the output of the recording-reproducing system. The magnitude of the change can be determined by measuring the AM and FM side bands which are generated in the process of recording and reproducing. The tape, as well as the transport design, will influence the side band amplitude. It is possible to predict the degree of amplitude modulation a recorded signal will exhibit by measuring the dc magnetization tape noise.
	Is Tape the Ideal Medium for Audio? 307785 bytes (CD aes2)
Author(s): Snyder, Ross H.
Publication: Volume 6 Number 2 pp. 99·101; March 1958
Abstract: All sound recording media possess limitations in signal-to-noise ratio, frequency range, distortion and economy. Each is characterized by more severe dynamic limitations at the frequency extremes than in the mid-range. the limits of present-day magnetic tape recording are explored, with special reference to slow-speed, high-information-density recording.
	Why Two Digital Video Formats? 682688 bytes (CD aes17)
Author(s): Watkinson, John
Publication: Paper SWP-B1; Conference: UK Conference: Sound with Pictures (SWP); April 1988
Abstract: There are now two digital video formats, D-1 and D-2, which have come about to solve different problems. This paper contrasts the formats and shows each of them in typical video systems.
	Surface Lubrication of Magnetic Tape 629441 bytes (CD aes9)
Author(s): Tobin, Henry G.; Powell, Carl
Publication: Preprint 1189; Convention 55; September 1976
Abstract: ITT Research Institute has developed a technique that greatly increases the operating life of the magnetic tape media as well as that of the head. This is accomplished by the application of a very thin coating of an inert lubricant to the surface of the media. Tests have been performed with a variety of commercially available tapes and various head materials. Greater than 5 million passes of 3M 900 on a loop tester were achieved with no apparent effect on the tape. Without lubrication, the same tests achieved only 30,000 passes. Head wear was decreased by as much as a factor of ten where lubricated tape was used. This paper describes the technique and gives typical test results obtained by IITRI and others.
	Proposed Equalization for 15 in/s Studio Master Recording on High-Output Low-Noise Tapes 403654 bytes (CD aes8)
Author(s): McKnight, J.; Kendall, T.
Publication: Preprint 920; Convention 45; April 1973
Abstract: A new equalization and reference fluxivity are proposed; no LF pre-emphasis, reproducing HF equalization +3 dB at 6300 Hz (·25 µs·), and fluxivity of 250 nWb/m. Measured data and a demonstration compare the NAB and proposed performances. Pre-emphasis at 4 kHz is increased from -2 to +1 dB; and at 16 kHz, from +1 to +6.5 dB (NAB was +11 dB in 1950, when developed). Noise and maximum signal at 4 kHz are thus reduced 3 dB (NAB was +11 dB in 1950, when developed). Noise and maximum signal at 4 kHz are thus reduced 3 dB, and at 16 kHz, 5.5 dB. Recording response with less than a total of 0.5 dB ripple up to 20 kHz is achieved with one RC equalizer.
	Modern Electronics in Colonial Williamsburg 294552 bytes (CD aes7)
Author(s): Squires, Charles C.
Publication: Preprint 461; Convention 31; September 1966
Abstract: Six channel foreign language film equipment and tape and public address equipment used in busses are described as used in a restored colonial town.
	Modulation Noise in Tape Recordings 381586 bytes (CD aes7)
Author(s): Langevin, Robert Z.
Publication: Preprint 391; Convention 17; September 1965
Abstract: This paper reviews some of the causes of amplitude and frequency modulation noise and suggests a simple measurement technique.
	Special Reproduce System for Independence Hall, Knott's Berry Farm 2523656 bytes (CD aes3)
Author(s): Hosoda, Akio J.
Publication: Volume 17 Number 1 pp. 55·60; December 1968
Abstract: This paper describes the basic design of the reproducer system and its special features, including the tape transport, with its automatic rewind and cue unit, and the tape assembly. The equipment necessary to make the recordings required for playback is also discussed.
	An Audio Noise Reduction System 678952 bytes (CD aes2)
Author(s): Dolby, Ray M.
Publication: Volume 15 Number 4 pp. 383·388; September 1967
Abstract: A noise reduction system which is suitable for use with high-quality audio recording or transmission channels is described. A special signal component, derived from four band-splitting filters and low-level compressors, is combined with the incoming signal during recording or sending. During reproduction, the additional component is removed in a complementary way; anØ noises acquired in the channel are attenuated in the process. Practical features of the system include: 10 dB (unweighted) noise reduction; imperceptibility of signal-modulated noise effects; level frequency response (overall); accuracy of reproduced signal dynamics; low distortion; low internal noise level; and stability of characters.
	Intermodulation Distortion in Tape Recording 530384 bytes (CD aes2)
Author(s): Langevin, Robert Z.
Publication: Volume 11 Number 3 pp. 270, 272, 274, 276, 278; June 1963
Abstract: The causes of intermodulation distortion in magnetic tape recording are discussed. A close correlation exists between harmonic distortion and intermodulation distortion measurements when the individual orders of distortion are measured separately. It is shown that nonsymmetrical input signals can be a source of intermodulation in tape recording. A session is suggested why our ear will tolerate high percentages of intermodulation distortion in music.

	332 of 9317 documents found     Page 5 of 17
	Title/Size/Author/Abstract
	High Speed Tape Duplication Up-To-Date 445567 bytes (CD aes2)
Author(s): Tinkham, R. J.; Isberg, R. A.
Publication: Volume 7 Number 3 pp. 125·128; June 1959
Abstract: Not available.
	The Standard Tape as a Professional Audio Tool 1684096 bytes (CD aes2)
Author(s): Richards, Frank F.
Publication: Volume 6 Number 3 pp. 193·196, 208; June 1958
Abstract: If the processional recordist is to achieve maximum results from the use of magnetic recording apparatus, standardization among recorders of such parameters as azimuth alignment, equalization, and bias level is a necessity. Precise instrumentation for such adjustments is extensive and expensive, which leads, on some occasions, to neglect. Most adjustments necessary to correct operation can be made with comparatively simple instrumentation and a Standard Tape of adequate precision. The manufacture of such tapes requires precision even beyond the normal necessities of high quality mastering. The method of manufacture and quality control is described, and the application of the tape to standard precision adjustment among recorders is explained.
	Solution to Some Problems in Making Master Tapes 507249 bytes (CD aes2)
Author(s): Tinkham, R. J.
Publication: Volume 5 Number 2 pp. 99·103; March 1957
Abstract: Not available.
	New Products and New Applications in the Magnetic-tape and Film Fields 3636967 bytes (CD aes2)
Author(s): Franck, Ernest W.; Schmidt, Edward
Publication: Volume 4 Number 3 pp. 90·100; June 1956
Abstract: In the last two years, advances in the manufacture and application of magnetic products have been made. This paper covers the physical and electrical characteristics of current standard tapes and Mylar tapes of various gauges. A report is given on ·print-through· characteristics of materials coated on base supports as thin as 0.5-mil Mylar. The use of striped magnetic film in motion pictures and in television is dealt with, as is the use of magnetic products for geophysical recording. Discussed, too, are strides which have been made in improving the friction characteristics of tape and film. These improvements, claim the authors, have solved some of the problems associated with telemetering and other instrumentation applications.
	Everything You Always Wanted to Know About Speed (But Were Afraid to Ask) 954546 bytes (CD aes9)
Author(s): Sleger, Roger R.
Publication: Preprint 1175; Convention 55; September 1976
Abstract: Is tape speed on current recorders accurate enough for you? A review of tape speed measurement techniques and standard is made as well as an assessment of their probable utility. Then the factors affecting tape speed on transports are explained in detail and their application in a new transport design is presented.
	Master-Tape Equalization Revisited 424136 bytes (CD aes8)
Author(s): McKnight, John G.; Hille, Peter F.
Publication: Preprint 856; Convention 42; April 1972
Abstract: Optimum signal minus noise level of a commercial tape or disc record requires the signal- and noise-spectra of the studio master tape to be matched to those of the commercial record. The use of the NAB 380 mm/s (15 in/s) equalization (3150 Hz transition frequency) with modern tapes results in frequency- and noise-spectra which have much higher levels at higher frequencies than the final records. Other practical equalizations are studied, and a 12,500 Hz reproducing transition frequency is suggested for further evaluation.
	Absolute Flux and Frequency Response Characteristics in Magnetic Recording: Definitions and Standardization 1782863 bytes (CD aes7)
Author(s): McKnight, John G.
Publication: Preprint 447; Convention 31; September 1966
Abstract: In order to have interchangeable tape recordings, standards are needed for frequency response characteristics and for the recorded flux. The quantities, terms, and definitions needed for this standardization are developed; the absolute flux and the wavelength response of the recorded signal are most appropriately expressed as the ·short-circuit remanent flux·; the ratio of this flux to the voltage input to the recorder is defined as the ·recording flux characteristic.· The need for equalization, and the division into recording and reproducing equalization, are developed. Standard equalization of many organizations are shown as ·flux characteristics.· Terms and definitions used in the various standards are compared with those developed here. This shows that the different standards are not consistent; different concepts are used, and the same terms have conflicting usages, resulting in confusion when standards are compared. Standard ·reference fluxes· are tabulated and briefly discussed. An extensive list of standards is appended.
	Specialized Equipment Used at the Columbia University Studio for the Production of Tape Music 2575517 bytes (CD aes7)
Author(s): Mauzey, Peter
Publication: Preprint 57; Convention 10; August 1958
Abstract: Many varieties of electronic and electomechanical apparatus have been used in experimental music studios throughout the world. Some of the most useful devices are standard commercial equipment; others have been specifically designed and constructed for the use of composers. This paper will describe such special apparatus in use at the Electronic Studio-Laboratory, Columbia University.
	A Multiformat Transportable Recording System 595492 bytes (CD aes13)
Author(s): Mosely, John
Publication: Preprint 4072; Convention 99; September 1995
Abstract: The author describes NTI's patented equalizer circuitry, illustrating various extensions of this technology to include microphone preamplifiers, active faders, and routing devices for high-quality audio. The devices have been built into a unique, multiformat, transportable, and self-contained digital recording system.
	Recording Low-Flutter Measurement Tapes: An Experimental Approach 565310 bytes (CD aes13)
Author(s): Cross, Lowell
Publication: Preprint 3842; Convention 96; January 1994
Abstract: A technique for recording measurement tapes with very low residual flutter has been the subject of an experimental investigation. A recorder with full transport servo was utilized to make high-speed recordings for measurement at standard speeds. The recorder has low inherent flutter, exceeding the manufacturerís specifications. A measurable improvement in the residual flutter of recordings made with this technique has been demonstrated and compared to the results obtained from the common method of recording at the playback speed.
	Evaluating Audio Inventions and Innovations 3684099 bytes (CD aes11)
Author(s): Thiele, Heinz H. K.
Publication: Preprint 2803; Convention 86; February 1989
Abstract: Solitary inventions and innovations can't be regarded as landmarks in the history of technical evolution; introduction to daily use is equally significant. Three examples in audio technology illustrate the ways in which the technical and economic development of magnetic recording have depended on the work of single individuals: Friedrich Plfeumer for magnetic tape development, von Braunmuhl/Dr. Weber in the field of AC biasing, John T. Mullin for effecting magnetic recording in the United States.
	Pre- and Post-Emphasis Techniques as Applied to Audio Recording Systems 1121782 bytes (CD aes10)
Author(s): Fielder, Louis D.
Publication: Preprint 2236; Convention 78; April 1985
Abstract: Audio Recorders benefit from pre- and post-emphasis which reshapes the noise spectrum to match human audibility thresholds. A 10dB increase in apparent dynamic range is realized for some digital-audio systems. A first order boost based on the CCITT J.17 pre-emphasis standard is shown to be appropriate for dynamic range expansion. A survey of peak acoustic levels present in 36 music performances is also included.
	The New Music and Media Facilities of the University of Colorado at Denver 1174345 bytes (CD aes9)
Author(s): Pritts, Roy A.
Publication: Preprint 1187; Convention 55; September 1976
Abstract: Presentation of audio recording facilities completed Fall, 1976, will be given. Design considerations specified by College of Music will be discussed. Structural, geometric, acoustic, electrical, and system designs will be shown. Completed three recording suites, rehearsal halls, control rooms, recording labs, and electronic maintenance will summarize.
	Low Frequency Response of Multitrack Magnetic Reproducers 627462 bytes (CD aes8)
Author(s): Melis, Jan; Nijholt, Bauke
Publication: Preprint E-4; Convention 44; February 1973
Abstract: When using full width recorded test tapes for multitrack recorders, there are a number of long wavelength deviations, yielding doubts about the real shape of the characteristic at the low end of the audio bandwidth. The special head, which erases the separation tracks of the full width recording so direct comparison becomes possible, is described.
	Vacuum Cassette Duplicator 1273537 bytes (CD aes8)
Author(s): Sleger, Roger R.; Harshberger, Jr., Robert P.
Publication: Preprint 891; Convention 43; August 1972
Abstract: A fully automatic 40:1 ·In Cassette Duplicator· has been developed that is based upon a small, servo controlled, vacuum tape transport. The system isolates the cassette mechanics from the duplicating area thereby enabling precise tape control at the heads. The principles of operation of the Ampex CD-200 vacuum duplicating system are presented.
	The Effect of Microphone and Loudspeaker Directional Characteristics Upon Recreating Acoustic Fields 987532 bytes (CD aes8)
Author(s): Long, Edward M.
Publication: Preprint 763; Convention 39; September 1970
Abstract: The importance of microphone and loudspeaker directionality is discussed and graphical data are presented. Both the acoustics of the initiating and reproducing environments, and the number of transmission channels dictate the choice of optimum microphone and loudspeaker directional characteristics and placement. Apparent discrepancies between theory and practice can often be traced to practical limitations of the transducers and/or environment.
	Some Aspects of High Frequency Loudspeaker Design 2277412 bytes (CD aes8)
Author(s): Long, Edward M.
Publication: Preprint 683; Convention 37; September 1969
Abstract: Graphical data are presented which relate to various aspects of high frequency loudspeaker design. Response uniformity, distortion, resonance, sensitivity, impedance, and dispersion are shown as functions of such parameters as cone material and shape, cone diameter, damping pads, rear chamber volume, etc. A step by step evolution of a particular high frequency loudspeaker is described and data given.
	Audio Facilities at AES Conventions·Their Development to the Present 588501 bytes (CD aes7)
Author(s): Joel, Irving L.; Russell, Hugh; Morris, Keith
Publication: Preprint 473; Convention 31; September 1966
Abstract: The evolution from existing house PA to the present integrated system tailored to our unique needs is described. The requirements of the talkers and the desire to provide high quality sound reinforcement led to changes in the system each year. The present system is the result of the past decade of experience with various equipment and locations.
	A Transistorized Professional Tape Recorder 883956 bytes (CD aes7)
Author(s): Oniki, Ben
Publication: Preprint 416; Convention 17; September 1965
Abstract: This paper discusses the problems of designing a recorder capable of recording at any of six tape speeds from 3-3/4 ips to 30 ips, with domestic or international versions of equalization, and with the widely varying record characteristics of the types of tapes in use today. Each equalizer is capable of being contained in a small plug-in housing. Two such housings for two different tape speeds with a relay to select the desired equalization are provided. The units treated will be: (1) in the reproduce section·the reproduce preamplifier, reproduce calibration amplifier and line amplifier; and (2) in the record section·the record calibration amplifier, record equalization circuit, record head amplifier, and the erase and bias oscillator. The design of the regulated power supply will be described, as well as the methods used to prevent audible disturbances being recorded on the tape when the record section is turned on or off.
	Precision Performance Measurements of a New Sound Recording Tape 988417 bytes (CD aes7)
Author(s): Kempler, Joseph
Publication: Preprint 365; Convention 16; September 1964
Abstract: Lack of standards and clear definitions make precise, repeatable performance tests on magnetic tape difficult. Typical problems and practical techniques for precise evaluation of sound tapes are described. These methods are used to compare a new high performance sound tape with older tapes.

	332 of 9317 documents found     Page 6 of 17
	Title/Size/Author/Abstract
	The Definition, Description, and Measurement of ·Flutter· 509258 bytes (CD aes7)
Author(s): McKnight, John G.
Publication: Preprint 190; Convention 13; September 1961
Abstract: Many methods have been used for measuring flutter; the proponents of each method claim theirs is the only proper method. In fact, however, the measurement parameters and equipment are determined by the purpose for measuring the flutter. Purposes are: to describe the effects of the flutter; to compare different transports by ·standard· measurements; and to analyze the causes of flutter for design purposes. These purposes are discussed, as are the measurement parameters and equipment appropriate to each purpose.
	A New Portable Stereo Mixer 745979 bytes (CD aes7)
Author(s): Wilkins, Charles A.; Bennett, John H.
Publication: Preprint 173; Convention 12; September 1960
Abstract: A two-channel mixer-amplifier with an unusual degree of versatility is described. The four-position mixer has input facilities for four microphones and two program lines. Two positions may select either line or microphone input. Each position may be elected to feed either or both of the two output channels. Mixers may be ·coupled· and/or ·stacked.·
	Increasing the Life of Your Audio Tape 441480 bytes (CD aes4)
Author(s): Wheeler, Jim
Publication: Volume 36 Number 4 pp. 232·236; March 1988
Abstract: Many factors necessary for long-term storage of audio tape are described, including a cool, dry environment and proper recorder maintenance. Several suggestions are given for measures to porolong the life of audio tape, as well as measures to use in recovering data when tape has suffered major damage. Recommendations are made for storing tape both in a home and in an archival environment.
	The Spectral Recording Process 1875761 bytes (CD aes4)
Author(s): Dolby, Ray
Publication: Volume 35 Number 3 pp. 99·118; February 1987
Abstract: A complementary audio signal encoding and decoding format, called spectral recording (SR), for use in professional magnetic recording and similar applications is described. The processing algorithm is highly responsive to the spectral properties of the signal. A further characteristic used by endoding deemphasizes high-level signal components in the frequency regions usually subject to channel overload. The process results in a significant reduction of audible noise and distortion arising in the channel.
	A 20 dB Audio Noise Reduction System for Consumer Applications 1657157 bytes (CD aes4)
Author(s): Dolby, Ray
Publication: Volume 31 Number 3 pp. 98·113; February 1983
Abstract: A 20 dB noise reduction system, designated C-type, for use in cassette tape recording and similar applications is described. An arrangement of two compressors and two expanders in cascade has been developed in which the signal-to-noise ratio improvement is compounded without significant accompanying increases of the overall maximum maximum compre;ssion and expansion ratio. Overshoots, modulation distortion, and noise modulation are well controlled. The maximum demands made on transmission channel uniformity are generally unchanged from those associated with the B-type system, although the uniformity requirements extend over a greater range of signal frequencies and levels. An improvement has been made in one condition of compressor/expander mistracking, namely, low-level mid-frequency signals in combination with dominant signals in the region above 10 kHz and incorrect channel response at such frequencies. A further development reduces the tendency of highly equalized channels to saturate, thereby increasing the useful signal levels which can be handled.
	CCIR/ARM: A Practical Noise Measurement Method 1006471 bytes (CD aes4)
Author(s): Dolby, Ray; Robinson, David; Gundry, Kenneth
Publication: Volume 27 Number 3 pp. 149·157; February 1979
Abstract: In 1972 Dolby Laboratories investigated techniques for measuring noise in professional and consumer audio equipment. A method giving agreement with subjective assessments was needed for use within the company and for exchanging information with outside organizations such as licensees. The study revealed that existing methods were unsatisfactory but that the use of the CCIR weighting characteristic with unity gain at 2 kHz in conjunction with an average responding meter (ordinary millivoltmeter) gave appropriate results. Practical details, circuitry, and applications are discussed.
	Flutter Analysis for Identifying Tape Recorders 937074 bytes (CD aes3)
Author(s): McKnight, John G.; Weiss, Mark R.
Publication: Volume 24 Number 9 pp. 728·734; October 1976
Abstract: Mechanical imperfections in every recorder cause speed variations (flutter) which have a frequency spectrum that is characteristic of both the model of recorder and of the individual recorder. The speed variation of the recorder cause fm sidebands around any signal recorded on that recorder. When the signal to be recorded contains a periodic signal, for instance power line hum, the sidebands on the recording can be measured, and converted into a flutter spectrum. By comparing the flutter spectrum found on the recording to that measured on the recorders, one may be able to identify the recorder which produced the recording. The theory is developed and a practical example is given.
	Optimum Use of Noise Reduction in FM Broadcasting 680200 bytes (CD aes3)
Author(s): Dolby, Ray M.
Publication: Volume 21 Number 5 pp. 357·362; May 1973
Abstract: A well-known problem in FM broadcasting is the excessive high-frequency preemphasis introduced by the 50- or 75-µs time constants now used. With modern program material the preemphasis results in possible overmodulation and the need for high-frequency limiting. If limiting is avoided in order to maintain signal integrity, then operation at an overall decreased level is required. The use of Dolby B-type compression during transmission provides an opportunity to reduce the preemphasis time constant to 25 µs, which permits the midband modulation level to be raised significantly with many types of program material. Listeners with conventional receivers are provided with a compatible signal but with the reception advantages of an increased modulation level. Listeners with 25-µs deemphasis time constants and B-type expanders have the dual advantages of increased level and lower noise.
	Weighted Peak Flutter Measurement·A Summary of the New IEEE Standard 267126 bytes (CD aes3)
Author(s): McKnight, J. G.
Publication: Volume 19 Number 10 pp. 859·861; October 1971
Abstract: The existing USA ·flutter content· standard (IEEE 193-1953 and ANSI Z57.1-1953) has been replaced by a new ·weighted peak flutter· standard (IEEE 193-1971 and ANSI S4.3-Draft). It standardizes the flutter meter specifications, the measuring procedures and the form for reporting results. Technical requirements are identical with those of CCIR and German standards and an IEC draft.
	Reliability in Production Testing of Loudspeaker Components and Systems 997804 bytes (CD aes3)
Author(s): Schroeder, Donald S.; Long, Edward M.
Publication: Volume 18 Number 2 pp. 133·139; March 1970
Abstract: The design and development of loudspeaker systems requires an anechoic room and much associated instrumentation to establish relative objective data and substantiate subjective results. Similar instrumentation for production testing of components and systems is described, which is not as accurate on an absolute scale but which requires less operation time and is more mobile. The correlation and calibration between laboratory and factory testing facilities is discussed.
	Audio Facilities for the Audio Engineering Society Conventions 1727897 bytes (CD aes3)
Author(s): Joel, Irving L.; Morris, Keith A.; Russell, Hugh N.
Publication: Volume 16 Number 1 pp. 52·60; December 1967
Abstract: The evolution of the audio facilities used at the annual conventions of the Audio Engineering Society is outlined, from the use of existing house public-address facilities to the current system which is a result of ten years' experience with a variety of equipment and in two locations. The console designed specifically for AES convention use is described.
	Transient Response and Phase Equalization in Magnetic Recorders 1382771 bytes (CD aes2)
Author(s): Johnson, Keith O.; Gregg, D. P.
Publication: Volume 13 Number 4 pp. 323·328, 330; September 1965
Abstract: Because of editing, balancing and other operations, magnetic recordings ultimately released by major studios may be many generations separated from the original recordings. Irregularities in transient response have not been commonly specified performance criteria in magnetic recorders. Nevertheless, these may detrimentally affect a multiple generation recording. In this paper the generation of phase distortion is explained in detail and solid state compensation techniques are analyzed. Examples of circuitry, waveform performance and test procedures are presented.
	Precise Performance Measurements on a New Sound Recording Tape 1138752 bytes (CD aes2)
Author(s): Kempler, Joseph
Publication: Volume 13 Number 1 pp. 50·56; December 1964
Abstract: Some of the problems introduced in the measurement of magnetic tape characteristics as a result of the lack of uniform test methods are discussed, and the procedures used by atape manufacturer for the production of own reference tapes and precise test equipment standardization are described. In addition, various precautions for assuring repeatability and accuracy of measurement are discussed and, finally, some test data obtained with the standardized equipment and methods on a new sound tape are presented.
	Dependence of Timbre on the Tonal Loudness Produced by Musical Instruments 359065 bytes (CD aes2)
Author(s): Clark, Jr., Melville; Milner, Paul
Publication: Volume 12 Number 1 pp. 28·31; December 1963
Abstract: To determine if the timbre of nonpercussive musical instruments are dependent upon the intensities with which they are played, musically competent subjects were asked to identify the various original dynamic markings with which the instruments were played from tones equalized in loudness by adjustment of the gain upon reproduction. Confusion matrices display the results. The timbre of nonpercussive musical instruments is, at most, a weak function of the intensity with which they are played, with a few exceptions.
	Flutter Measurements by the American Standard Method 460468 bytes (CD aes2)
Author(s): Morgan, Donald E.
Publication: Volume 9 Number 3 pp. 232, 234, 238; June 1961
Abstract: Not available.
	The Electrostatic Earphone 381713 bytes (CD aes2)
Author(s): Selsted, W. T.
Publication: Volume 9 Number 2 pp. 145·147; March 1961
Abstract: The construction of a pair of electrostatic earphones is described. The most unique characteristics of such a device are the sound reproduction quality and the acoustical transparency.
	Tape Duplicating Systems for Talking Book Program 640964 bytes (CD aes2)
Author(s): Himmelstein, S.
Publication: Volume 9 Number 2 pp. 102·106; March 1961
Abstract: The requirements for an efficient, high speed duplicating system for the Talking Book Program are defined. Consideration is given to production of intermediate and duplicating masters as well as the final listener tape. Equalization the the problem of recording and reproducing high speed index material are also discussed. It is shown that standard equipments, with minor modifications, can be used to handle the foreseeable Talking Book requirements for the next twenty-year period.
	A Low-Distortion Volume Expander for Home Use 1162467 bytes (CD aes2)
Author(s): Matthys, R. J.
Publication: Volume 8 Number 3 pp. 199·205; June 1960
Abstract: The proper design of a volume expander is discussed. The problems of feedback, low distortion, linear expansion, maximum thump cancellation, and attack and decay time selection are covered in detail. The performance of an expander built using the design ideas discussed is given. The expander has 19 db of expansion and 0.5-msec attack time. The expander adds more life to music and makes more pleasant listening.
	Why Stereo? The Philosophy of Multichannel Recording of Music 402277 bytes (CD aes2)
Author(s): McKnight, John G.
Publication: Volume 8 Number 2 pp. 87·90; March 1960
Abstract: Two effects which contribute greatly to our enjoyment of live music are the ability to locate the source of the sound (stereophony) and the feeling of being in a good concert hall (ambiophony). These effects and their relationship to music are discussed. Microphone placement in multichannel recording is seeen to depend on which effect is to be recreated in the home, and to what degree.
	Design and Development of an Engineering Report 537158 bytes (CD aes2)
Author(s): Goodall, George B.
Publication: Volume 8 Number 1 pp. 41·45; December 1959
Abstract: Project engineers are being called on to present an increasing number of written reports covering the design and development programs they supervise. Many of them feel that professional writing ability is required and that the demands on their time preclude more than a cursory interest in these important documents. This paper shows that an orderly and logical presentation of material is more important than skillful writing techniques and relates the organization of the report to a simple engineering problem. It explains why the engineer should originate the reports on his project and the growth in professional stature that will result.

	332 of 9317 documents found     Page 7 of 17
	Title/Size/Author/Abstract
	Time Errors in Magnetic Tape Recording 675724 bytes (CD aes2)
Author(s): Prager, Roger H.
Publication: Volume 7 Number 2 pp. 81·88; March 1959
Abstract: A theoretical treatment of time errors encountered in magnetic tape recording is developed. Effects of random noise are considered, as well as motional effects (flutter). Experimental results, obtained using an Ampex Model 3078 two-channel tape recorder and an Axis-Crossing Interval Meter, are presented. The use of autocorrelation methods to predict and measure flutter characteristics is discussed in detail.
	Some Experiences with Mass-Production Tape Duplicating 2717290 bytes (CD aes2)
Author(s): Bidlack, Cecil S.
Publication: Volume 4 Number 1 pp. 31·37; December 1955
Abstract: Not available.
	System Design for Multiple Copying of Tape and Disk Program Material 212824 bytes (CD aes2)
Author(s): Winston, Robert D.
Publication: Volume 2 Number 1 pp. 34·35; December 1953
Abstract: Not available.
	Phase Distortion in Audio Magnetic Recording 584974 bytes (CD aes9)
Author(s): Heaslett, Alastair M.
Publication: Preprint 1178; Convention 55; September 1976
Abstract: This paper reviews some of the important factors influencing the overall phase nonlinearity of magnetic recording as applied to audio usage, and the effect of these nonlinearities on multiple generation copying. A new record equalizing scheme is described which provides a considerable degree of inherent phase correction and which produces a recording whose phase characteristics are compatible with normal reproducing equalizing standards.
	A Closed-Loop Tape Transport Servo System for Pressure Roller-Less Drive 2318417 bytes (CD aes9)
Author(s): Harshberger, Jr., Robert P.
Publication: Preprint 1174; Convention 55; September 1976
Abstract: The servo control system used in a new audio tape transport is discussed with special emphasis on the requirements dictated by continuous capstan tape control. Closed loop reel and capstan servos, their modes of operation, interaction, and control, along with some of the unusual methods employed in their implementation will be presented.
	Control of Modulation Noise in Magnetic Recording Tape 903065 bytes (CD aes8)
Author(s): Mills, David; Kristensen, Helge; Santos, Virgilio
Publication: Preprint 1084; Convention 52; September 1975
Abstract: Factors in the formulation and manufacture of magnetic tape which contribute to the problem of modulation noise have been defined. The effects of formulation variables (oxide, binder and additive types and proportions) are relatively small. The effects of manufacturing variables, particularly calendering, are very large. Improvements in modulation noise of 12 dB were found when the calendering process was optimized. The best calendering process requires the use of homogeneous compliant rolls instead of the composite type previously used. Infrared transmission microscopy was developed as a useful technique for identifying and controlling the calendering-related modulation noise.
	Weighted Peak Flutter Measurement: A Summary of the New IEEE Standard 311178 bytes (CD aes8)
Author(s): McKnight, J. G.
Publication: Preprint 814; Convention 41; September 1971
Abstract: The existing USA ·flutter content· standard (IEEE no. 193-1953 and ANSI Z57.1-1953) has been replaced by a new ·weighted peak flutter· standard (IEEE no. 193-1971 and ANSI S4.3-draft). It standardizes the flutter meter specifications, the measuring procedures, and the form for reporting results. Technical requirements are identical with those of CCIR and German standards, and an IEC draft.
	A Review of German DIN Standards on Sound Recording and Reproducing with Magnetic Tape 746404 bytes (CD aes7)
Author(s): McKnight, John G.
Publication: Preprint 277; Convention 14; September 1962
Abstract: The German Industrial Standards (DIN) prescribe most of the important mechanical and electrical characteristics of magnetic tape recording equipment, and the appropriate measuring methods. The thirteen pertinent standards which are reviewed might well serve as a guide for developing comparable standards in the USA.
	A Benchmark for Digital Audio in the Real World of 1989 5756596 bytes (CD aes16)
Author(s): Ludwig, Bob
Publication: Paper 7-018; Conference: The AES 7th International Conference: Audio in Digital Times; April 1989
Abstract: Not available.
	Splice Handling Mechanisms in Dash Format 616354 bytes (CD aes10)
Author(s): Watkinson, J. R.
Publication: Preprint 2199; Convention 77; February 1985
Abstract: The DASH format for digital audio multitrack recording supports tape cut editing. The paper explains in detail how this requirement largely determined the format, along with the interleave structure and error correction strategy. The supporting circuitry necessary to handle splices is also detailed, with particular reference to servo phasing problems and the mechanism for making a synchronous recording over a splice.
	Dynamic Range Requirement for Subjective Noise Free Reproduction of Music 853501 bytes (CD aes10)
Author(s): Fielder, Louis D.
Publication: Preprint 1772; Convention 69; April 1981
Abstract: A dynamic range of 118 dB is determined necessary for subjective noise-free reproduction of music in a dithered digital audio recorder. Maximum peak sound levels in music are compared to the minimum discernible level of white noise in a quiet listening situation. Microphone noise limitations, monitoring loudspeaker capabilities, and performance environment noise levels are also considered.
	A Thirty-Five Year History and Evolution of the Recording Studio 1411545 bytes (CD aes9)
Author(s): Putnam, Milton T.
Publication: Preprint 1661; Convention 66; April 1980
Abstract: An historic review of the three and one half decades from the mid forties to 1980, provide a most interesting period of development of the recording studio, control room, and reverberation rooms and devices. Some basic fundamental techniques have weathered the test of time. The evolving changes in design concept occurred as a a result of the drastic shift in the music idiom, the major improvements in recording technology, and the need for cosmetic and esthetic alteration to accommodate the performers' wishes.
	A Reversible 8 Track Cartridge 686594 bytes (CD aes9)
Author(s): Smith, K. Rey
Publication: Preprint 1489; Convention 63; April 1979
Abstract: Present 8-track tape cartridges have a major flaw·they cannot be reversed·to edit, or hear program material again. This paper describes the design of a Reversible 8-track cartridge, which has been tooled and will be distributed this summer. Emphasis is placed on the design details of the molded spring system and its relationship to the tape tension.
	A Codeword Controlled Multi-Standard Recorder Design for Digital Audio Application and a New Approach to Digital Recorded Program Editing 678926 bytes (CD aes9)
Author(s): Blüthgen, Björn
Publication: Preprint 1465; Convention 63; April 1979
Abstract: Several hardware manufacturers have already published their digital audio recorder parameters. The author aims to overcome the implied standardization problems and to avoid future drawbacks arising from fixed parameters by introducing a "codeword controlled multi-standard recorder design" described below. In addition, an editing concept is considered which enables digital audio program editing and punch-in without disturbing crossover effects, even on razor-spliced tapes.
	Magnetic Design of Tape Recorder Heads 1413465 bytes (CD aes9)
Author(s): McKnight, John G.
Publication: Preprint 1375; Convention 60; April 1978
Abstract: This paper gives the circuit models, the formulas, and a BASIC language computer program for calculating the efficiency, frequency response, and complex impedance of a magnetic recording or reproducing head. The model and the calculations take into account the effects of the complex permeability of the elements: a core of non-homogeneous limitations of specified thickness and geometry; a front gap with non-conducting or conducting gap spacer; gap stray permeance; and a rear gap. Measurements presented on seven different heads varify the model and the calculations.
	Magnetic Digital Audio Recording: A Realistic Look at an Emerging Technology 1745193 bytes (CD aes9)
Author(s): Engberg, E.W.
Publication: Preprint 1339; Convention 59; January 1978
Abstract: The general considerations towards the design of Magnetic Digital Audio Recorders are presented and a typical block diagram is explained. Some areas of hardware implementation which are considered state-of-the-art are discussed to provide the potential user with a realistic understanding of what will limit the performance specifications of digital audio recorders. Certain machine operating requirements which the author feels are necessary for the general acceptance of digital recorders are presented to show their dependence upon the recorders basic signal and tape formats.
	Transient Intermodulation Distortion and Measurement 2734759 bytes (CD aes18)
Author(s): Stanley, Gerald; McLaughlin, Dave
Publication: Preprint 1308; Convention 58; October 1977
Abstract: Increasing sophistication of equipment and user demands an updating of test methods to insure useful test results. Amplifier test methods are investigated, with particular attention to the question of audibility of the types of distortion thus revealed. A proposal for a new test method is discussed, in particular as it reveals transient intermodulation distortion. Examples and results of tests are considered, and implications for amplifier design are drawn.
	Longitudinal Digital Recording of Audio 821829 bytes (CD aes9)
Author(s): Warnock, Richard B.
Publication: Preprint 1169; Convention 55; September 1976
Abstract: This paper describes a two channel digital recording system intended for highest quality audio use. A criterion for the system has been the achievement of all the potential improvements promised by the application of digital techniques to audio; such as dynamic range expansion, elimination of wow and flutter, eliminating the need for noise reduction systems, and elimination of tape hiss, while avoiding the major difficulties typical of this application. Most of these goals have been met in this system by the application of existing technology and theory.
	The Effect of Conducting Gap Spacers on the Impedance of Magnetic Heads 713156 bytes (CD aes8)
Author(s): Otto, Rudolph
Publication: Preprint 841; Convention 42; April 1972
Abstract: The impedance of magnetic recording heads at high frequencies is reduced by making the gap spacer of conducting material, because eddy currents in this conductor lower the permeance of the gap region. The traditional formulae for the complex permeability vs frequency of a conducting lamination (as used in transformer design) apply within the gap area. The formulae involve spacer initial permeability, resistivity and the gap depth which corresponds to the usually-used lamination thickness. Measurements of impedance vs frequency of a large ·model· head verify the theory.
	Stop Using the Ambiguous dBM! 1263964 bytes (CD aes8)
Author(s): Wilms, Herman A. O.
Publication: Preprint M01; Convention 2ce; February 1972
Abstract: Absolute decibels, especially the dBm, are still subject to much confusion and many mistakes. A historical survey of the dB is given, which ends in the new standard IEC 268. This standard abandons further use of the dBm, where the dB re 0.775 V no more corresponds to a definite symbol. A new term is proposed and some other new points of view are given.

	332 of 9317 documents found     Page 8 of 17
	Title/Size/Author/Abstract
	The Fringing Response of Magnetic Reproducers at Long Wavelengths 499933 bytes (CD aes8)
Author(s): McKnight, John G.
Publication: Preprint 800; Convention 40; March 1971
Abstract: When a recorded track is wider than the reproducing head, the apparent tape flux at long wavelengths is increased. This produces a boost in low-frequency response, and a measuring error in the ·level set· and the frequency response of a multitrack reproducer playing a full-track test tape. Normalized graphs (based on Grimwood's formula) are given which show the appropriate level corrections for common reproducing systems.
	Design Parameters of a Dual Woofer Loudspeaker System 2034734 bytes (CD aes8)
Author(s): Long, Edward M.
Publication: Preprint 655; Convention 36; March 1969
Abstract: During the initial design stage of a new speaker system the possibility of using a dual woofer approach was investigated. While the theoretical advantages of two woofers over one of the same size are well known, there are also advantages over a woofer of the next larger standard size. It was determined that even greater gains could be achieved if the new woofers were specifically designed for dual operation. Other factors such as tweeter design and mounting and crossover technique are discussed.
	Reliability in Production Testing of Loudspeaker Components and Systems 2025043 bytes (CD aes18)
Author(s): Schroeder, Donald S.; Long, Edward M.
Publication: Preprint 641; Convention 36; March 1969
Abstract: The design and development of loudspeaker systems requires an anechoic room and much associated instrumentation to establish relative objective data and to substantiate subjective results. Similar instrumentation is employed for production testing of components and systems which is not as accurate on an absolute scale, but which requires less operation time and is more mobile. The need arises for a system of correlation and calibration between laboratory and factory to allow for these differences while retaining sufficient accuracy to guarantee the desired quality level of the product.
	Low Noise Replay·Preamplifier for Professional Audio Recorders 719225 bytes (CD aes8)
Author(s): Vajda, Zoltan
Publication: Preprint 632; Convention 36; March 1969
Abstract: In one of the forthcoming issues of the Journal of the Audio Engineering Society, a professional audio recorder will be described in some detail. The recorder has been designed and manufactured in Hungary and is used widely in the Hungarian Radio and Television and in the broadcasting and recording organizations of the neighboring countries. The preamplifier to be described here is a part of this recorder.
	The Development of the Simulated Live-vs-Recorded Test into a Design Tool 341644 bytes (CD aes7)
Author(s): Kissinger, John R.
Publication: Preprint 609; Convention 35; September 1968
Abstract: Loudspeakers and systems are commonly designed using anechoic chambers for sound pressure response curves and reverberation chambers for power-available-efficiency curves. These frequency responses, while repeatable, represent extreme acoustic conditions and do not necessarily correlate to average listening conditions which are semi alive environments. Jensen Engineers attempted to design a listening test that could be performed in the average living room. The test should meet the Engineering criterion of repeatability with different operators and different living rooms. As is common in N.A.S.A. space shots we achieved a partial success.
	A Random Access Audio Retrieval System 343493 bytes (CD aes7)
Author(s): Kuljian, Maynard J.
Publication: Preprint 576; Convention 34; March 1968
Abstract: This system, the first of its type, represents a significant advance in the art of information retrieval. It is a complete random access audio system for a learning resources center. Computer controlled magnetic tape units, organized for high-speed duplication, permit rapid access and playback of any of hundreds of master programs. Features include individual student control of both playback and recording, programs which always start at the beginning, a maximum waiting time of less than 60 seconds for any number of users, a small integrated control/display unit which can be located rmotely in classrooms and other buildings, and telephone interconnections to permit outside calling. The number of programs and student positions is limited only by the space available and by cost considerations.
	An Improved, Low Crosstalk Recording Head Designed for Sync Playback 277493 bytes (CD aes7)
Author(s): Dace, Warren B.
Publication: Preprint 563; Convention 34; March 1968
Abstract: When the first professional tape recorders, with provision for synchronous playback from the recording head, were put on the market a few years ago by Ampex Corp., they were immediately accepted by the recording industry. Today most recording studios would consider it out of the question to purchase a multi-channel recorder without this feature. The pre-recorded tracks, played back from the record head, were meant to be used for cur purposes only, but studio engineers soon put this feature to another use. The track or tracks, played through the record head were mixed with other material from microphones in the studio and then re-recorded onto another track on the same tape. This procedure is known as ·ping-ponging.· The requirement that a single head must be able to record a signal on one track while simultaneously playing back a signal on another track, presents several problems in head manufacture.
	The NAB Recording and Reproducing Standards 320904 bytes (CD aes7)
Author(s): Braun, Warren L.
Publication: Preprint 536; Convention 33; September 1967
Abstract: The NAB Recording and Reproducing Standards Committee was originally organized in 1941. Standards proposals concerning Disc and Magnetic Tape (reel-to-reel) have been by the NAB Board in 1942, 1949, 1950 and 1953. These standards and recommended good engineering practices are for the guidance of the broadcasting industry. In 1964 and 1965 the Standards Committee completely revised its past audio standards and added to its list Cartridge Tape Recording and Reproducing. This paper will review past and current standards and activities of the NAB.
	Report on a Seminar in Electronic Music Composition 421681 bytes (CD aes7)
Author(s): Deutsch, Herbert A.
Publication: Preprint 431; Convention 17; September 1965
Abstract: A report on the organization of a seminar and workshop for composers of electronic music. This seminar under the auspices of the R. A. Moog Co., took place in August. Delivered from a composer's and teacher's viewpoint, this paper reports discussions of techniques, problems, esthetic considerations and notation encountered during the seminar. Exemplary musical compositions will be included if feasible.
	Optimum Performance in Audio Transistor Amplifiers Using Resistive or Inductive Sources 661680 bytes (CD aes7)
Author(s): Jepsen, David B.
Publication: Preprint 339; Convention 16; September 1964
Abstract: This report describes the noise figure of a transistor amplifier in the grounded emitter configuration. The effects of biasing, and emitter resistances are included in the noise figure. When the signal source is an inductance such as the reproduce head of a magnetic recorder, the signal-to-noise ratio (S/N) is better measurement of amplifier performance. It is shown that the S/N ratio can be maximized by a suitable choice of inductance, depending upon the operating conditions of the transistor.
	A System for High-Speed Multiple Duplication of Three-Track 15/16 IPS Magnetic Tape Cartridges 4665125 bytes (CD aes7)
Author(s): Kaiser, Arthur; Mahler, Henry
Publication: Preprint 317; Convention 15; September 1963
Abstract: This paper describes the duplicating center developed for the Library of Congress magnetic talking book program. Operating at sixteen times playback speed, this system can simultaneously reproduce 10 3-track cartridges in any combination of three different books without removal of tape from cartridge. A production speed-up ratio of 300 to 1 is realized. A full description is furnished of the system electronics, automatic controls and performance specifications.
	Trends in Magnetic Recording·Reappraisal III 1177011 bytes (CD aes7)
Author(s): Camras, Marvin
Publication: Preprint 316; Convention 15; September 1963
Abstract: Improvements in transducers, transports, record media, and cartridges will be reviewed; unfulfilled prognostications of former years explained; and a new forecast made.
	Single Ended Electrostatic Loudspeakers with High Efficiency and Improved Linearity 846545 bytes (CD aes7)
Author(s): Johnson, Keith O.
Publication: Preprint 283; Convention 15; September 1963
Abstract: An electrical circuit analogue is developed to give the electrical input acoustical output characteristics for electrostatic loudspeakers. A single ended wide range tweeter, having one watt output to 200 cps, is designed with the model and has an electro-acoustic feedback loop and tapered diaragm supports. Tests with a pink noise source and a spectrum analyzer are described.
	Noise Considerations in Tape Reproduce Amplifiers 575092 bytes (CD aes7)
Author(s): Skov, Erling P.
Publication: Preprint 264; Convention 14; September 1962
Abstract: The increasing demand for higher signal-to-noise ratio in audio reproduction combined with the use of narrow trackwidths and lower tape speeds make it necessary to use very low noise amplifiers. In this paper, the different types of noise found in a head-amplifier combination will be described. The different types of tape noise will not be included.
	Intermodulation Distortion in Tape Recording 545945 bytes (CD aes7)
Author(s): Langevin, Robert Z.
Publication: Preprint 244; Convention 14; September 1962
Abstract: The various forms of intermodulation distortion in recorded sine waves and in musical chords were investigated to determine their cause and effect on listening quality.
	Subjective Evaluation of Factors Affecting 2-Channel Stereophony 1017360 bytes (CD aes7)
Author(s): Harvey, F.K.; Schroeder, M.R.
Publication: Preprint 136; Convention 12; September 1960
Abstract: In transmitting and reproducing two-channel stereophonic signals, the original program material may be modified deliberately or unintentionally. Separation upper and lower cut-off frequencies as well as full-band channel separation (in db) have been evaluated subjectively in terms of detection of spatial difference, preservation of spatial resemblance and listener preference. In addition, other pertinent observations on subjective aspects are reported.
	Design and Development of an Engineering Report 554000 bytes (CD aes7)
Author(s): Goodall, George B.
Publication: Preprint 132; Convention 11; September 1959
Abstract: Project engineers are being called on to present an increasing number of written reports covering the design and development programs they supervise. Many of them feel that professional writing ability is required, and that the demands on their time preclude more than a cursory interest in these important documents. This paper shows that an orderly and logical presentation of material is more important than skillful writing techniques, and relates the organization of the report to a simple engineering problem. It explains why the engineer should originate the reports on his project, and the growth in professional stature that will result.
	Why Stereo? The Philosophy of Multi-Channel Recording of Music 308229 bytes (CD aes7)
Author(s): McKnight, John G.
Publication: Preprint 120; Convention 11; September 1959
Abstract: Two effects which contribute greatly to our enjoyment of live music are the ability to locate the source of the sound (stereophony) and the feeling of being in a good concert hall (ambiophony). These effects and their relationship to music are discussed. Microphone placement in multi-channel recording is seen to depend on which effect is to be recreated in the home, and to what degree.
	Fifty Years of Loudspeaker Developments as Viewed Through the Perspective of the Audio Engineering Society 3982910 bytes (CD aes6)
Author(s): Gander, Mark R.
Publication: Volume 46 Number 1/2 pp. 43-58; December 1997
Abstract: An exhaustive review of over 450 AES Journal loudspeaker papers and other select references is presented and categorized by subject area. The names and affiliations of the authors are included. Perspective is given on the technical significance, degree of influence, and historical context of the contributions and contributors. Except where otherwise noted, all references are from the Journal of the Audio Engineering Society and, where applicable, the volumes of the AES Loudspeakers anthology.
	Dynamic-Range Requirement for Subjectively Noise-Free Reproduction of Music 810708 bytes (CD aes4)
Author(s): Fielder, Louis D.
Publication: Volume 30 Number 7/8 pp. 504·511; June 1982
Abstract: A dynamic range of up to 118 dB is determined necessary for subjectively noise-free reproeuction of music in an audio recorder with a white-noise floor. Maximum peak sound-pressure levels in music are compared to the minimum discernible level of white noise in a quiet listening situation. Microphone noise limitations, monitoring loudspeaker capabilities, and performance environment noise levels are also considered.

	332 of 9317 documents found     Page 9 of 17
	Title/Size/Author/Abstract
	Motion Picture Sound in Record-Industry Perspective 1765730 bytes (CD aes4)
Author(s): Moseley, John
Publication: Volume 29 Number 3 pp. 114·125; February 1981
Abstract: This tutorial paper deals with the historical developmentn of motion picture sound. It traces the areas that are cast in concrete and are bewildering to people schooled in the record industry.
	Long-Wavelength Response of Magnetic Heads with Beveled Outer Edges 524507 bytes (CD aes4)
Author(s): Lindholm, Dennis A.
Publication: Volume 27 Number 7/8 pp. 542·547; June 1979
Abstract: The long-wavelength response of magnetic reproduce heads with beveled outer edges has been numerically computed. To show contributions from both cross-sectional geometry and head (track) width, several beveled heads have been studied and compared with rectangular heads for two limiting cases: infinite head width and zero head width. The calculations demonstrate that the long-wavelength oscillations associated primarily with the length of the rectangular head with zero width are much stronger than those of the corresponding head with infinite widthl. Head performance can be greatly improved, however, with a proper beveled cut which greatly decreases these oscillations and lessens sensitivity to head width.
	A Comparison of Measured and Calculated Fringing Response of Multitrack Magnetic Reproducers 759005 bytes (CD aes4)
Author(s): Melis, Jan; Nijholt, Bauke
Publication: Volume 26 Number 4 pp. 212·216; March 1978
Abstract: When using full-width recorded calibration test tapes for multitrack reproducers, there are a number of long-wavelength response factors which cause doubts about the real shape of the response factors at low frequencies. The effects responsible for these deviations are discussed. They are measured by an empirical procedure using a special head which erases the guard bands from a full-width recording so that a direct comparison becomes possible between the full-track recording and the multitrack recording.
	Loudspeaker Standards and Loudspeaker Performance Limitations 339384 bytes (CD aes3)
Author(s): Small, Richard H.
Publication: Volume 21 Number 2 pp. 117·119; February 1973
Abstract: Overstringent specifications on the minimum low-frequency performance levels of domestic high-fidelity loudspeaker systems lead to designs requiring either large enclosures or high electrical driving powers.
	EIA RS-400 ·Reproducer Test Tape· Reviewed 312670 bytes (CD aes3)
Author(s): McKnight, John G.
Publication: Volume 21 Number 2 pp. 115·117; February 1973
Abstract: The specification for a full-track one-quarter-inch (6.3-mm) width open-reel test tape has been published by EIA. It is for a dual-purpose tape for 3.75- and 7.5-in/s (95- and 190-mm/s) tape speeds, containing a reference flux per width (not program reference) of 100 nWb/m; a coarse and a fine asimuth adjusting section; and a point-by-point frequency response section following the NAB flux-frequency response with minor modifications. Extensive user instructions and comments on the development of the standard are included.
	The Effect of Conducting Gap Spacers on the Impedance of Magnetic Heads 705367 bytes (CD aes3)
Author(s): Otto, Rudolf
Publication: Volume 20 Number 4 pp. 258·264; April 1972
Abstract: The impedance of magnetic recording heads at high frequencies is reduced by making the gap spacer of conducting material, because eddy currents in this conductor lower the permeance of the gap region. The traditional formulas for the complex permeability versus frequency of a conducting lamination (as used in transformer design) apply within the gap area. The formulas involve spacer initial permeability, resistivity, and the gap depth which corresponds to the usually used lamination thickness. Measurements of impedance versus frequency of a large ·model· head verify the theory.
	The Effects of Transit Time and Intensity Differentials Upon Recreating Acoustic Fields 1093602 bytes (CD aes3)
Author(s): Long, Edward M.
Publication: Volume 20 Number 2 pp. 82·91; February 1972
Abstract: The importance of transit time and intensity differentials in the sounds picked up by microphones and reproduced by loudspeakers is discussed. The relationship of sources and microphones, as well as loudspeakers and a listener is discussed and graphic examples are presented. Much of the difficulty encountered in attempting to recreate an acoustic field can be traced to the fact that the acoustic pressure varies with the square of the distance, while the transit time for an acoustic wave is a linear function of distance.
	Audio Cassette Chromium Dioxide Tape 2829875 bytes (CD aes3)
Author(s): Naumann, Klaus E.; Daniel, Eric D.
Publication: Volume 19 Number 10 pp. 822·828; October 1971
Abstract: Chromium dioxide particles differ from iron oxide particles in several respects. The saturation magnetization and coercivity are higher and, as illustrated by electron micrographs, the particles are more acicular and more readily oriented. It is shown that these physical properties give rise to substantial improvements in audio recording performance, particularly at the very short wavelengths involved in high quality cassette recording.
	Comments on "Perceptibility of Wow and Flutter" 186088 bytes (CD aes3)
Author(s): McKnight, John G.
Publication: Volume 18 Number 4 pp. 440, 441; July 1970
Abstract: Not available.
	Comments on ·A Plea for Accurate Terminology· 79093 bytes (CD aes3)
Author(s): McKnight, John G.
Publication: Volume 18 Number 4 p. 440; July 1970
Abstract: Not available.
	A Trailerized Acoustic Shell for Outdoor Performances of Symphony Orchestra and Concert Opera 1809623 bytes (CD aes3)
Author(s): Jaffe, Christopher; Quaintance, Peter; Swisher, Charles
Publication: Volume 17 Number 6 pp. 671·677; November 1969
Abstract: This paper describes the design and development of the Minnie Guggenheimer Shell used by the New York Philharmonic and the Metropolitan Opera to present free outdoor summer concerts to audiences of up to 70,000 people in each of the five boroughs of New York City. This portable concert hall system has been in operation for five years, since the summer of 1965, and is the only one of its kind in the world.
	A Studio Tape Recorder of Novel Design 3591449 bytes (CD aes3)
Author(s): Vajda, Zoltan
Publication: Volume 17 Number 6 pp. 634·643; November 1969
Abstract: The basic design principles and constructional details of a new two speed 1/4 in. mono-stereo studio tape recorder are described. The tape transport of the machine is divided into seven separate modules which can be lifted easily from the cast aluminum frame of the transport. Reed relays are used throughout except for motor switching; the unit incorporates a simple transistor logic requiring only 16 contacts for the whole transport with full remote control. The circuits used in the electronic units are conventional, except for the reproducing preamplifier which uses a very low-noise amplifier. The technical specifications of the recorder are shown as statistical distributions of the measured data from a large number of recorders, and the editing accessories as well as a version of the basic recorder built for synchronous recording in motion pictures are described.
	A Differential Telephone Repeater Circuit 341191 bytes (CD aes3)
Author(s): Dessen, Joseph H.
Publication: Volume 17 Number 5 pp. 572, 576, 578; September 1969
Abstract: Not available.
	Design Parameters of a Dual Woofer Loudspeaker System 1403067 bytes (CD aes3)
Author(s): Long, Edward M.
Publication: Volume 17 Number 5 pp. 515·524; September 1969
Abstract: During the initial design stage of a new loudspeaker system, the inability of many compact bookshelf loudspeaker systems to reproduce, with realism, the ·impact· sounds of percussion instruments was related in part to the acoustic response shape. An acoustic method of increasing the output in the 200 to 600 Hz range was found in the mutual coupling of two woofers. Woofer and tweeter design and the effects of mounting on tweeter response are discussed. Crossover technique and the effects upon acoustic output due to driver phasing are also discussed.
	Measuring a Tape Reproducer with IEC-Response, Using NAB-Response Test Tape 121036 bytes (CD aes3)
Author(s): McKnight, John G.
Publication: Volume 17 Number 5 p. 572; September 1969
Abstract: Not available.
	The NAB Recording and Reproducing Standards 936108 bytes (CD aes3)
Author(s): Braun, Warren L.
Publication: Volume 16 Number 2 pp. 168·173; March 1968
Abstract: Not available.
	A Seminar in Electronic Music Composition 274336 bytes (CD aes2)
Author(s): Deutsch, Herbert A.
Publication: Volume 14 Number 1 pp. 30·31; December 1965
Abstract: Not available.
	Duration of Attack Transients of Nonpercussive Orchestral Instruments 591539 bytes (CD aes2)
Author(s): Luce, David; Clark, Jr., Melville
Publication: Volume 13 Number 3 pp. 194·199; June 1965
Abstract: The durations of the attack transients of various nonpercussive orchestral instruments have been measured statistically. The durations varied from one instrument to another, with the note played on the instrument, and with the particular player. The durations were not significantly dependent upon the dynamic marking of the note played or the duration of the tone sounded, or upon whether the instrument was played with vibrato or not. Least-squares parabolas were fitted to the values of the durations as a function of note number. The ratio of the root-mean-square deviation from the parabola to the average duration changes rather little from one instrument to another. The durations range from 0.014 sec to 0.085 sec and increase in the order: double reeds, clarinet, brass, strings, flute.
	The Case Against Low-Frequency Pre-Emphasis in Magnetic Recording 230617 bytes (CD aes2)
Author(s): McKnight, John G.
Publication: Volume 10 Number 2 pp. 106·107; March 1962
Abstract: Data on low-frequency energy distirbution in music do not justify the use of low-frequency pre-emphasis, and subjective low-frequency noise does not require it. Therefore the elimination of low-frequency pre-emphasis is suggested. Practical implications are also discussed.
	Subjective Evaluation of Factors Affecting Two-Channel Stereophony 997511 bytes (CD aes2)
Author(s): Harvey, F. K.; Schroeder, M. R.
Publication: Volume 9 Number 1 pp. 19·28; December 1960
Abstract: In transmitting and reproducing two-channel stereophonic signals, the original program material may be modified deliberately or unintentionally. Separation upper and lower cutoff frequencies as well as full-band channel separation (in db) have been evaluated subjectively in terms of detection of spatial difference, preservation of spatial resemblance, and listener preference. In addition, other pertinent observations on subjective aspects are reported.

	332 of 9317 documents found     Page 10 of 17
	Title/Size/Author/Abstract
	High-Resolution Stereo Magnetic Head for Four-Track Application 689535 bytes (CD aes2)
Author(s): Sariti, A. A.
Publication: Volume 8 Number 4 pp. 243·245; September 1960
Abstract: Design criteria for slow-speed narrow gap in line stereo head cartridge application are discussed. Actual results of production heads built to these specifications are reviewed.
	The Tape-Head Relationship in Multitrack Recording 236208 bytes (CD aes2)
Author(s): Leslie, Frazer
Publication: Volume 8 Number 2 pp. 130·131; March 1960
Abstract: This paper evaluates the basic tape-to-head relationship that applies in multitrack recording in comparison to that relationship in monophonic operation. It studies such factors as frequency response, crosstalk, signal-to-noise ratio, distortion, and tape drop-outs, and shows that the only significant difference that occurs in multitrack recording is a small deterioration in the signal-to-noise specifications. The mechanical considerations of azimuth alignment and gap-to-gap spacing are also discussed.
	Magnetic Tape Recording with Longitudinal or Transverse Oxide Orientation 544212 bytes (CD aes2)
Author(s): Dubbe, Richard F.
Publication: Volume 7 Number 4 pp. 203·206, 216; September 1959
Abstract: A comparison of the performance of magnetic tape when the recording field is in the same direction as, or perpendicular to, the oxide particles as encountered in magnetic disc or video recording.
	The Processes of Experimental Music 875694 bytes (CD aes2)
Author(s): Ussachevsky, Vladimir A.
Publication: Volume 6 Number 3 pp. 202-208; June 1958
Abstract: To produce musical compositions directly from recorded sound, novel methods of sound manipulation have been evolved by three distinct groups of composers and engineers in the United States and in Europe. Constant experimentation has produced a few commonly used and a few specialized processes such as: sound prolongation and shortening, extensive spectrum transformation through artificial reverberation, tape-speed variation and multi-channel filters, and intricate tape splicing. Problems of distortion arise from sund manipulation, and from the repeated re-recording and mixing of many tracks of tape. Composers and engineers have a new ground for fruitful creative collaboration far beyond merely sharing their knowledge of the routine aspects of each other's art. Many problems must yet be solved through a long range program of research, but the growth of this new medium of expression seems assured, although subject to the usual dangers of cheap commercialization.
	An In-Line Two-Channel Magnetic Head of Universal Application 417270 bytes (CD aes2)
Author(s): Sinott, Richard; Sprinkle, Melvin
Publication: Volume 5 Number 2 pp. 86·89; March 1957
Abstract: A newly designed two-track magnetic tape head is described, which has high crosstalk rejection between adjoining channels. This permits use of the design in a single head which may be used for full-track, half-track, and two-track stereophonic use. The basic design incorporates crosstalk rejection of 60 db in the mid-audio frequency range. Crosstalk rejection of this order makes·on a practical basis·inter-channel crosstalk as low as or lower than the signal-to-noise ratio in machines of professional quality. Short discussions and explanations are included on the causes of inter-channel crosstalk, including that from transformer action and that from magnetic fields about the tape itself. The head is simple to produce with reproducible characteristics from head to head and channel to channel.
	The Audio-visual Requirements of the Overseas Missionary 2330116 bytes (CD aes2)
Author(s): Gallina, Harold
Publication: Volume 5 Number 1 pp. 4·10, 31; December 1956
Abstract: The ever-increasing use of audio-visual aids by overseas mission personnel emphasizes the need for equipment which will meet the vagaries of foreign operations. This paper describes (1) the effects of uncertain power and climatic conditions upon audio equipment, (2) the technical services offered by the author's organization, and (3) new devices designed to meet special requirements for overseas use such as (a) a playback attachment for 16mm magnetically striped film, (b) a simplified tape recorder attachment for synchronizing dialogue to a slide or film-strip projector, and (c) a mobile audio-visual unit.
	Bibliography of Magnetic Recording 1981755 bytes (CD aes2)
Author(s): Jorysz, Alfred
Publication: Volume 2 Number 3 pp. 183-199; June 1954
Abstract: Not available.
	Decorating the Home with Music 382271 bytes (CD aes2)
Author(s): Tinkham, Russell J.
Publication: Volume 1 Number 4 pp. 302·304; September 1953
Abstract: Music in the home should be considered as much a part of interior decor as decorative fabrics, colors, and furnishings. The development of new recording and reproducing techniques makes possible home music that reflects the character of the home owner. Just as music relieves tension in busy factories, offices, and stores, it can be used to sooth the busy homemaker.
	Digital Audio in MAGNUM DVTR 1110588 bytes (CD aes11)
Author(s): Watkinson, John
Publication: Preprint 2359; Convention 80; February 1986
Abstract: MAGnetoscope NUMerique is the name of the EBU working group which in co-operation with the SMPTE and other parties has proposed a standard for a digital video recorder for professional use. This paper concentrates specifically on the digital audio system of the DVTR and illustrates how the special requirements of video recording have determined many of the parameters, and have resulted in techniques not found in audio only recorders. The block structure of the audio data will be described, in order to illustrate how sectoring is used to permit independent editing of the audio channels. It will be shown that the format permits different degrees of flexibility in audio editing, allowing at one extreme simple circuits for portable recorders and at the other extreme complex post production recorders. The necessary processes to perform track bouncing, synchronous recording, split audio edits and variable crossfade times will be described, and it will be explained why post production machines will need extra heads. A further topic will be the ability to unlock the audio sampling rate from the television frequencies.
	Design of an Electronic Music Composition Studio 706579 bytes (CD aes9)
Author(s): Cottle, James G.
Publication: Preprint 1686; Convention 67; September 1980
Abstract: The creative aspect of electronic music require unique approaches to the design of electronic music composition studios. Space and budget limitations compound the decision making process required to realize synergy between analog and digital synthesis equipment, professional recording equipment, and accurate acoustics. These problems were successfully addressed in the design of the SYCOM (Systems Complex for the Studio and Performing Arts) Studio A facility at the University of South Florida. Design of this facility brought together techniques from the fields of music, computer science, acoustics, and electrical engineering.
	Design Criteria for Digital Audio Tape 495093 bytes (CD aes9)
Author(s): Granum, Freeman
Publication: Preprint 1279; Convention 58; October 1977
Abstract: General construction and requirements of all magnetic tape are reviewed. Differences between the recording of analog and digital signals are discussed as they pertain to the magnetic medium. The pecularities of magnetic tape suitable for recording of digital information are examined. Particular emphasis is placed on dropout testing and total tape surface integrity as a function of the interplay of track spacing and recording format.
	Use of the Multi-Track Recorder as a Composing Aid in Electronic Music Systems 276798 bytes (CD aes8)
Author(s): Pritts, Roy A.
Publication: Preprint 1075; Convention 52; September 1975
Abstract: Use of magnetic tape for storage, manipulation, and assemblage of the elements of electronic music composition has been the object of research and practice for many years. Application of these procedures to digital as well as analog information provides the electronic composer today with a wide variety of new possibilities for altering and reassembling compositional elements, as well as new methods of digital manipulation and control. The object of composition has not changed, but new technology and the artistic application that comes from command of latest developments in systems provides for new compositional techniques.
	Intensities of Orchestral Instrument Scales Played at Prescribed Dynamic Markings 784744 bytes (CD aes7)
Author(s): Clark, Melville; Luce, David
Publication: Preprint 328; Convention 16; September 1964
Abstract: The intensities of scales played on nonpercussive orchestral instruments at various dynamic markings and the resulting dynamic ranges are reported. We are able to deduce the size quanta corresponding to one step in a dynamic marking and the number of quanta in the dynamic range of a musical instrument using deviations from smoothed curves. The average dynamic range of the nonpercussive orchestral instruments in about 11 db between the dØnamic marking of pianissimo and fortissimo; the average intensity at 10 meters is about 59 db re 0.0002 dynes/cm2.
	Standards Setting at BSI 470021 bytes (CD aes17)
Author(s): Underwood, Justin
Publication: Paper WBL-03; Conference: UK Conference: Will You Be Legal? (WBL); February 1991
Abstract: The British Standards Institution is the primary UK national standards body and it also represents UK interests in the areas of international and European standardization. I am a member of two BSI technical committees, one concerned with audio and video recording, and the other with magnetic recording for instrumentation applications. Most of the activity relevant to AES members comes under the aegis of BSI Technical Committee EEL/32, Equipment and Systems In The Field Of Audio, Video and Audio-visual Engineering. My own field, recording, is handled by another committee designated EEL/22. Sadly, little work in the overall field of electronics leading to new standards now occurs in the UK. The only developments of new tape recording formats now taking place in Britain are for military applications, and there are very few of these. However, both EEL/22 and EEL/32 are kept very busy as we participate very actively in international work.
	Feature Film Sound for Television 916299 bytes (CD aes17)
Author(s): Yonge, Mark
Publication: Paper SWP-A3; Conference: UK Conference: Sound with Pictures (SWP); April 1988
Abstract: Stereo sound for television will require suitable material from a number of sources. In the cinema, stereo sound has been accepted for over 35 years. Originally this was a special premiere facility, however, since 1975 Dolby Stereo optical soundtracks have provided a high quality, low-cost stereo format for general cinema release. These high quality, wide range tracks are suitable for television transfer. A simple adaption to conventional telecine equipment is required. As well as providing stereo and improved mono performance, these stereo transfers provide material that can be presented in full cinema-style stereo in the home using Dolby Surround decoder.
	Format Choices for the Future 93674 bytes (CD aes16)
Author(s): Shaw, Kenneth
Publication: Paper 9-033; Conference: The AES 9th International Conference: Television Sound Today and Tomorrow; January 1991
Abstract: Not available.
	Television Sound and Viewer Perceptions 319943 bytes (CD aes16)
Author(s): Neuman, W. Russell; Crigler, Ann N.; Bove, V. Michael
Publication: Paper 9-019; Conference: The AES 9th International Conference: Television Sound Today and Tomorrow; January 1991
Abstract: This study examines the impact of changes in audio quality on viewer perceptions of the television viewing experience. A sample of 367 mass audience viewers recruited from a shopping mall were randomly assigned to conditions which included low fidelity vs. high fidelity, monaural vs. stereo and three types of television programming. Viewers watched a series of short video clips with varying audio quality and asked to rate their liking, level of interest and psychological involvement in the programming and asked to evaluate picture and audio quality. Our mass audience subjects did not prove to be very discriminating. They had a difficult time distinguishing mono from stereo and even low fidelity from high fidelity sound. In a mono/stereo comparison 41% preferred stereo, 34% preferred mono and 24% heard no difference. In the low fidelity-high fidelity test 43% preferred high fidelity, 27% preferred low fidelity and 30% heard no difference. The strongest differences in preference were apparent in comparing low fidelity mono to high fidelity stereo television audio. We conclude that high fidelity television audio and stereo imaging need to be introduced in tandem in order to have significant psychological impact on untrained audience members. As an interesting sidelight, we discovered that video with better quality and stereo sound were consistently rated as more likable, interesting and involving. Viewers also rated programming with better audio as having higher picture quality, but this occurred in only one of the three test programs we ran.
	Sound Systems for Educational Theaters 1526109 bytes (CD aes16)
Author(s): Thomas, Richard K.
Publication: Paper 6-018; Conference: The AES 6th International Conference: Sound Reinforcement; April 1988
Abstract: Not available.
	Conference Participants 171383 bytes (CD aes16)
Author(s): Strawn, John
Publication: Paper 5-022; Conference: The AES 5th International Conference: Music and Digital Technology; April 1987
Abstract: Not available.
	Stereo Audio Transfer Considerations: Some Observations and Thoughts 302729 bytes (CD aes16)
Author(s): Hart, Alan A.
Publication: Paper 4-008; Conference: The AES 4th International Conference: Stereo Audio Technology for Television and Video; April 1986
Abstract: All businesses have conscious or unconscious philosophies which establish their goals and operating methods. Success today can only be achieved if one of the conscious philosophies is quality control. We at Modern Videofilm hold to the philosophy that the primary purpose of the post production transfer facility is to create a high quality video and audio master which is an accurate representation of the original film both technically and aesthetically. Maintaining this philosophy has required that comprehensive quality control procedures be implemented during all phases of transfer and dubbing.

	332 of 9317 documents found     Page 11 of 17
	Title/Size/Author/Abstract
	Standardization in Professional Digital Audio Engineering at the AES 460644 bytes (CD aes16)
Author(s): Locanthi, Bart
Publication: Paper 3-008; Conference: The AES 3rd International Conference: The Present and Future of Digital Audio; May 1985
Abstract: The author will discuss events leading up to the AES involvement in digital audio standards, some obstacles along the way, our present position, and the outlook for future standards.
	Toward an Aesthetic in Mixing for Multichannel Music Presentation 1026023 bytes (CD aes14)
Author(s): Mitchell, Doug
Publication: Preprint 4818; Convention 105; August 1998
Abstract: Changes in the approach to mixing various music formats are necessary to present concepts for new multichannel presentation technologies. This paper explores these changes in a real-world teaching environment. The paper focuses upon the alterations in pedagogy and presents examples of approaches to an aesthetic appropriate for mixing music in a multichannel environment.
	The 25 Essential Steps in the Development of Analogue Magnetic Sound Technology 8198154 bytes (CD aes14)
Author(s): Thiele, Heinz H. K.
Publication: Preprint 4708; Convention 104; April 1998
Abstract: This presentation about the development of analog magnetic sound technology attempts to describe inventions, new procedures, components, equipment, ranges of application, as well as markets and events, all of which offer information about changing technology standards.
	Sydney University's Graduate Program in Audio 1263148 bytes (CD aes13)
Author(s): Bartolo, David; Dash, Ian; Fekete, Pal; Fricke, Fergus; Scott, Jonathan; Thiele, Neville
Publication: Preprint 4322; Convention 6r; August 1996
Abstract: The need in Australia for higher education and continuing professional development in audio has been recognized for some time. This paper describes the process of setting up the graduate audio program at Sydney University, its structure, philosophy behind it, teaching techniques used, articulation with other programs, possible future developments, and research directions.
	Digital Mastering of the Mercury Living Presence Recordings for Compact Disc Release 331341 bytes (CD aes12)
Author(s): Drake, Dennis M.
Publication: Preprint 3242; Convention 92; February 1992
Abstract: Music purists believed it was impossible to capture on compact disc the power and ambience of the original Mercury Living Presence LPs. A custom analog to digital chain was developed with the restoration and use of original tube and film equipment. Topics include production methods employed, tube versus transistor comparisons, and the goal of maintaining the original natural sound while working in the digital domain.
	Spectral Contamination Measurement 5932560 bytes (CD aes11)
Author(s): Jensen, Deane; Sokolich, Gary
Publication: Preprint 2725; Convention 85; October 1988
Abstract: The "spectral contamination" measurement is a graphic spectrum analysis of cross modulation products produced in a nonlinear (any real-world) amplifier or system which is excited by a multi-frequency signal. The system under test is excited at defined frequencies and the resulting nonlinear distortion products are analyzed at other frequencies where no excitation energy is present. It is our hope that this method of measurement will ultimately enable us to correlate objective measurement results with subjective impressions of audio components, a goal which has eluded many traditional distortion measurements.
	A Television Station High-Quality Audio Wiring System 752148 bytes (CD aes11)
Author(s): Wolfe, Michael; Fast, Bill
Publication: Preprint 2544; Convention 83; September 1987
Abstract: It is not often that an opportunity to design and install a system in a totally new environment presents itself. Many recent changes encourage a strong emphasis on a clean design of audio-for-video. The relatively recent interest by consumers in the audio component of television broadcasting as a result of the advent of stereo has resulted in an increased emphasis on the quality of the audio signal. Quality audio can be an important factor for a PBS station competing in a major market. Coming in the near future are digital audio signal storage and processing. New and different circuitry presents the opportunity for more effective audio system design. These, and other, factors, encouraged the engineering management of KCTS to give high priority to the audio system.
	Standardization in Professional Digital Audio Engineering at the AES 442515 bytes (CD aes11)
Author(s): Locanthi, Bart N.
Publication: Preprint 2320; Convention 80; February 1986
Abstract: The author will discuss events leading up to the AES involvement in digital audio standards, some obstacles along the way, our present position, and the outlook for future standards.
	Standardization in Professional Digital Audio Engineering at the AES 444783 bytes (CD aes10)
Author(s): Locanthi, Bart N.
Publication: Preprint 2278; Convention 79; September 1985
Abstract: The author will discuss events leading up to the AES involvement in digital audio standards, some obstacles along the way, our present position, and the outlook for future for future standards.
	Implementation of the Sony PCM-F1/SL-2000 for Low-Cost Field Recording 460965 bytes (CD aes10)
Author(s): Streicher, Ron
Publication: Preprint C1008; Convention 2i; April 1984
Abstract: On-location recording is a requirement of almost every recording engineer at some time in his career, and there are as many methods of approaching the project as there are projects to be done. Among the considerations in planning the session are: 1) The environment for the recording; acoustics, ambient noise, comfort, space and facilities, AC power, transportation, etc.; 2) the logistics; access for setup and working times, continuity of sectional sessions, security of the personnel and equipment, tear-down and load-out; 3) the equipment needed to perform the recording session; the proper microphone complement, mixing console, interface equipment, communications devices for use between the studio and control room areas, monitoring facilities, and, of course, tape recorders and tape stock. It is not the province of this paper to discuss all of these factors, but merely to comment on the practical realizations of using the Sony PCM-F1 recording system as the chosen recording medium.
	Audiooptics·The Next Technology 1255581 bytes (CD aes10)
Author(s): Bowley, George A.
Publication: Preprint 2013; Convention 74; September 1983
Abstract: Audiooptics is a newly emerging technology which integrates the principles of audio engineering and optical techniques to effect improvements in existing methods of reproducing sound and transmitting audio signals. Audiooptics produces quantum improvements in the performance of audio systems used in broadcasting, recording, and music industries by taking advantage of the attributes of fiber-optic sensor, communications, and optical processing techniques to eliminate induced noise and hum, cable attenuation, frequency response constraints, nonlinearity, and electrocution hazards.
	Equalizing Tape Recorder Head Bumps 721409 bytes (CD aes10)
Author(s): Dugan, Dan
Publication: Preprint 1901; Convention 72; September 1982
Abstract: Most analog tape recorders exhibit head bump variations in low-frequency response. When companding noise reduction is used the effect of head bumpes becomes the most prominent defect in recordings. The use of dedicated semi-fixed parametric equalizers to flatten recorder response has improved the quality of the authorís tape production.
	Channel Codings for Digital Audio Recordings 1471538 bytes (CD aes10)
Author(s): Doi, Toshi T.
Publication: Preprint 1856; Convention 70; September 1981
Abstract: Channel coding is very important in order to obtain high density recording and high reliability at the same time. Several new channel codes are developed for the improvement of digital audio recordings. In this paper, the fundamental parameters for the evaluation of channel codes are described, and several conventional codes are explained with the application to the present digital audio systems. In comparison to those, new codes are discussed. One of the new codes is applied to the format of professional digital audio recorders. The other is applied to Compact Disc Digital Audio Systems.
	Electrical Reproduction of Acoustically Recorded Cylinders and Disks 4086032 bytes (CD aes10)
Author(s): Owen, Tom; Fesler, John C.
Publication: Preprint 1854; Convention 70; September 1981
Abstract: This paper will discuss the audio restoration and electrical recording of the Napleson cylinders from the 1901, 1902, and 1903 Metropolitan Opera seasons. Original Edison blanks were shaved and recorded (under controlled conditions) with pink noise, tone sweeps, digital-generated-frequency-source signal, and simultaneous recording, acoustically and electrically, of a wind ensemble. Acoustical analysis, groove analysis, wax formulation, surface-to-noise content, and horn-resonance frequencies were sampled and plotted. Slides and musical examples verify the results achieved.
	A Listening Comparison of Far-Field Microphone Techniques 510993 bytes (CD aes10)
Author(s): Shafer, Robert T.
Publication: Preprint 1753; Convention 69; April 1981
Abstract: Far-field pickup of large musical ensembles can use coincident, near-coincident, or spaced microphone arrays. After a brief theoretical introduction, an orchestra recording made by using the three microphone techniques simultaneously on multiple recorders will be demonstrated. . The demonstration tape has been edited to sequentially present the three basic techniques. Audible differences from each technique can then be easily compared.
	Motion Picture Sound in Record Industry Perspective 1215960 bytes (CD aes9)
Author(s): Mosely, John
Publication: Preprint 1668; Convention 66; April 1980
Abstract: This tutorial paper deals with the historical development of motion picture sound. It traces the areas that are cast in concrete and are bewildering to people schooled in the record industry.
	Maintenance Procedures for Ferrite Heads 1459875 bytes (CD aes18)
Author(s): Manquen, C. Dale; Martinson, Joe
Publication: Preprint 1508; Convention 63; April 1979
Abstract: Ferrite heads have been steadily growing in popularity in the professional audio field for the last ten years. Beginning with high speed tape duplicator applications, ferrite has worked its way into the high-end consumer market and the top line professional market. Table 1 lists some of the advantages and disadvantages of ferrite, but by far the greatest selling point has been long life·typically ten times the life of conventional laminated metal heads. This advantage, however, vanishes if the head experiences gap chipping or erosion which produces premature catastrophic head failure. This paper deals with methods of diagnosing ferrite gap chipping by studio maintenance personnel to avoid catastrophic failures.
	VU Meter and Peak Program Meter--Peaceful Coexistence 451953 bytes (CD aes9)
Author(s): Temmer, Stephen F.
Publication: Preprint 1474; Convention 63; April 1979
Abstract: Much has been written of late, too much, I fear, about the virtues and shortcomings of both the Standard Volume Indicator (vu meter for short), and the Peak Program Meter (PPM). All that aside, the world faces the reality of both instruments and needs to understand their use, meaning, and relationship to each other. There never was any problem with this as long as each country stayed with its traditional instrument. Part of the reason lies in the introduction of PPM's by U.S. manufacturers on consoles, tape machines, or the meters themselves, while several European manufacturers in traditionally PPM oriented countries, have put vu meters on their tape recorders. The result is that many studios now have a mixture of vu and PPM meters alongside one another. This paper is intended to clarify the alignment and operation of studio equipment using either or both of these meters.
	Trends in Audio Education·A Symposium 1422204 bytes (CD aes18)
Author(s): Wilson, Geoffrey L.; Johnson, Kenneth W.; Lodge, Tom; Yackish, Thomas M.; Gadhoke, Raghu; Manquen, C. Dale
Publication: Preprint 1379; Convention 60; April 1978
Abstract: In an attempt to find answers to this frequently posed question (and there is no one answer) several educational programs typical of those currently being offered will be described by a panel of faculty members. The panel is augmented by recent students who will describe their own experience, and by representatives from industry. We think that this interchange of ideas will be of interest to educators, prospective students, and practicing engineers alike, and should provoke a stimulating discussion.
	The Permeability of Liminations for Magnetic Recording and Reproducing Heads 661323 bytes (CD aes9)
Author(s): McKnight, John G.
Publication: Preprint 1265A; Convention 57; April 1977
Abstract: Although catalog values or the maximum permeability of head materials such as 4-79 mo-permalloy are about 300 000 µ0., the practical values for initial permeability at 1000 Hz for thin laminations bonded together into a head core are more nearly 5000 µ0 to 10 000 µ0. The initial permeability of a toroid or a "gapless" head may be calculated from physical dimensions and an inductance bridge measurement. The Maxwell bridge with a variable capacitance works especially well.

	332 of 9317 documents found     Page 12 of 17
	Title/Size/Author/Abstract
	Magnetic Recording and the 20th Century Musician: The Inlaws and the Outlaws 341220 bytes (CD aes9)
Author(s): Pritts, Roy A.
Publication: Preprint 1262; Convention 57; April 1977
Abstract: Inside the world of musicians to observe how magnetic tape recording has changed the rules of the game, how artists have learned to utilize the new vehicle, and have found a new pipeline to audiences. Observations on artists who have become milestones and an overview of oxide art. Looking at recent advances to predict the possibilities of musical evolution.
	On the Calibration of the Magnetic Recording 992799 bytes (CD aes9)
Author(s): Kogure, Takuyo; Sakamoto, Narajii; Tsunoh, Tadaaki
Publication: Preprint 1160; Convention 55; September 1976
Abstract: The calibration of audio magnetic tape recording presents various problems with respect to accuracy. One problem involves the calibration of the standard recording level of the reference signal and another the calibration of the frequency characteristics of the lower and higher ranges. To solve these problems, we have discovered a new method related to the reference signal which is both practical and precise compared with the ordinary method in the field of magnetic tape recording equipment. We are also introducing a new method for the calibration in the lower range by using a single turn "loop head," and also calibration in the higher range by measuring the "spacing loss" in relation to the surface roughness on the magnetic head. Finally an explanation is given of the newly developed test tape recording process, which is controlled by a "mini-computer system."
	Magnetic Head Relapping Techniques 415800 bytes (CD aes9)
Author(s): Dundovic, Joseph F.
Publication: Preprint 1122; Convention 54; April 1976
Abstract: Worn heads can be reliably refinished by the user to give performance to that of the original head. Procedures and required materials are described to achieve a professionally relapped head in approximately five minutes. A head can usually be refinished once or twice before being completely worn out.
	A High Speed Digital to Analog Conversion System for Digital Music Synthesis 451418 bytes (CD aes9)
Author(s): Wood, Thomas
Publication: Preprint 1121; Convention 54; April 1976
Abstract: A general review of the parameters necessary to provide acceptable D/A conversion for music, a description of the high-speed (100K sampling rate), high resolution (16 bit) system used by the Indiana University School of Music, and comments on new hardware.
	Development of a Voice Projection System for Masked Firefighters 1902266 bytes (CD aes8)
Author(s): Giordano, Thomas J.; McClean, Mark
Publication: Preprint 1054; Convention 52; September 1975
Abstract: Firefighters often wear protective breathing devices utilizing face masks. Voice communication through these tasks is very difficult, especially in noisy locations. A comprehensive study of the electroacoustic and mechanical requirements for a high quality firefighter's speech projection system has been made. A system tailored to a new U.S Navy breathing apparatus has been developed, giving highly intelligible voice communications to the user.
	A Study of Time Domain Speech Compression By Means of a New Analog Speech Processor 936702 bytes (CD aes8)
Author(s): Bennett, I. M.; Linvill, J. G.
Publication: Preprint 1044; Convention 51; April 1975
Abstract: Time domain speech compression using the SDA (sample, discard, abut) procedure at compression ratios of 0.25 0.75 is studied by means of a new analog speech processor and minicomputer algorithms. Fourier transform methods have been used to establish correspondence between the quality of the reconstructed compressed speech waveforms and the subjective recognition of compressed speech. The result of two psychoacoustic experiments indicate that: 1. The interruption frequency should be equal to the pitch frequency of the voice waveform for the optimum recognition of the compressed speech. 2. Smoothing of the discontinuities with electronic techniques significantly improves the recognition of the compressed speech. The optimum smoothing parameters, window-width, and characteristic function are also obtained from this study.
	PEM 468: A New Mastering Tape with High-Output, Low-Noise and Low-Print Characteristics 364036 bytes (CD aes8)
Author(s): Singhoff, W.; Vogeding, A.
Publication: Preprint 1036; Convention 51; April 1975
Abstract: New oxide developments and new manufacturing technologies allowed development of a mastering tape with extended electro-acoustic characteristics concerning maximum output level, bias noise and print through. Technical data will be given and measuring techniques discussed. US and European standards and conditions will be compared. The material is outstanding by a favorable combination of low noise and low print properties. A special matte backing treatment allows winding on hubs without support flanges.
	Multitrack Audio in Video Production 454263 bytes (CD aes8)
Author(s): Nothaft, Eugene M.; Irby, Tom W.
Publication: Preprint 877; Convention 43; August 1972
Abstract: The topic to be discussed in this paper is the multitrack audio machine usage in double system recording. This is a situation where the video and audio portions are recorded on separate machines. The film industry has used this technique successfully for a number of years; however, due to the problems encountered in synchronizing two non-sprocketed machines, the television industry has been slow to adopt this technique.
	Dolby B-Type Noise Reduction for FM Broadcasts 710437 bytes (CD aes8)
Author(s): Robinson, David P.
Publication: Preprint 820; Convention 41; September 1971
Abstract: Experiments were carried out recently to test the effectiveness of the Dolby B-type noise reduction system in reducing the noise of FM transmissions, particularly for stereo reception where the operation of the multiplex decoder degrades the signal to noise ratio by 23 dB. Test results, which will be described in the paper, show that the system is effective in reducing this noise as well as other forms of high frequency interference such as SCA ·monkey chatter.· The 10 dB noise reduction can be equated to an increase of ten times in transmitter power, or a three times increase in service area.
	Sound Effects Systems, Simple and Complex 644210 bytes (CD aes8)
Author(s): Klepper, David L.; Piacentini, Vincent
Publication: Preprint 788; Convention 40; March 1971
Abstract: Use of sound creatively in theater is expanding, and every space where drama is performed requires a sound-effects system. Sound effects playback over systems designed for reinforcement is satisfactory only in special cases. Systems ranging from simple adaptations of packaged tape recorders with built-in amplifiers to fully professional combinations of custom consoles, professional tape and disc equipment, and portable theater-type loudspeakers are discussed. Simple operation and provisions for expansion are important.
	Measurement of Microphone Characteristics 5172552 bytes (CD aes8)
Author(s): Arnold, David
Publication: Preprint 787; Convention 40; March 1971
Abstract: Microphones have many characteristics that are critical parameters affecting their successful usage. Frequency response and sensitivity are the most commonly specified characteristics, but there are many more factors that could be specified and indeed must be controlled to permit a manufacturer to make a usable microphone. A number of these characteristics are described and measurement techniques as used by Shure Brothers Incorporated are discussed. Items included are frequency response, sensitivity, polar pattern, wind and pop noise, structure-borne noise, distortion, electrical noise, and others.
	A Dropout Detector for Testing Multi-Channel Tape for Re-Use 443047 bytes (CD aes8)
Author(s): McLean, Michael
Publication: Preprint 748; Convention 39; September 1970
Abstract: After the best ·take· has been clipped out of an original session tape reel, it is desirable to bulk erase the remaining tape for re-use. A dropout detector unit has been designed to detect poor splices, tape damage, etc., to assure that the tape is in good condition. Design details are described, along with a discussion of the practical application consideration.
	Signal Conditioning for Slow Speed Tape Recordings 720744 bytes (CD aes8)
Author(s): Wood, James B.
Publication: Preprint 686; Convention 37; September 1969
Abstract: This paper investigates the various difficulties encountered in producing slow speed prerecorded tapes from wide range source material, particularly heavily equalized rock music. Circuitry which was developed to cope with certain spectral energy distribution problems is discussed and the results demonstrated.
	A Sound Reinforcement System for Multiple Conference Rooms 774932 bytes (CD aes8)
Author(s): Draper, Melvin S.
Publication: Preprint 642; Convention 36; March 1969
Abstract: This paper discusses design and application of a new two-way acoustic transducer for use in multiple sound reinforcement systems inter-connected via regular telephone lines. This device provides hands-off voice inter-communication between large numbers of attendees in several remote conference rooms. The omnidirectional microphone and speakers are included in a single assembly with pickup sensitivity and output radiation adequate for most conference rooms. High gain-before-feedback is accomplished by the unique design and by acoustic phase cancellation.
	A User-Oriented Quality Tape Duplicator 612768 bytes (CD aes7)
Author(s): Wood, James B.
Publication: Preprint 613; Convention 35; September 1968
Abstract: This paper describes a user-designated high speed tape duplicating system adaptable to standard 4- or 8-track continuous loop cartridges or Phillips cassettes. Particular attention was given to features of operational simplicity, ease of maintenance, and use flexibility. Also discussed are the advantages of several electronic circuit innovations which are departures from ·classic· design.
	High Density Disc Recording Systems 533147 bytes (CD aes7)
Author(s): Levens, Leo M.
Publication: Preprint 604; Convention 35; September 1968
Abstract: Continuing investigation in the field of high density disc recording has resulted in a record with a playing time of 20 hours. Some of the history and reasoning underlying this development will be presented. A description of the processes and elements of the system will follow. The potential of high density disc recording system will be assessed. The reproduction of the discs at the rate of 4-1/6 rpm will be demonstrated.
	A Brief View of EIA Standards in the Audio Field 525197 bytes (CD aes7)
Author(s): Caffiaux, J. A.
Publication: Preprint 535; Convention 33; September 1967
Abstract: A full understanding of the significance of any standard benefits from a knowledge of the formulating body, its organization, its standards procedures, and the degree to which it prolulgates. For this reason, this paper includes, in the first three sections, background information on EIA, its Engineering Department, and its Standardization Procedures. The main body of the paper identifies twenty-five EIA Standards relating to the Audio field in such categories as Broadcasting, Sound Systems, Loudspeakers, Pickups, Stylii, Phones, Disc and Magnetic Recording and Power Output Ratings. The content of some of the more widely used of these standards is described, as well as new standards efforts under development.
	A Professional Studio Monitor Loudspeaker System 910646 bytes (CD aes7)
Author(s): Long, Edward M.
Publication: Preprint 466; Convention 31; September 1966
Abstract: With the development of a professional studio monitor loudspeaker system as a goal, steps were taken to analyze the problems involved. It was decided early that the means of evaluating the reproducing accuracy were as important as the techniques used to achieve the desired results. A study was made of program material, microphone characteristics and recording techniques. Master tapes were used during the development.
	Sound/Communication Systems: The Sound Contractor's Viewpoint 971842 bytes (CD aes7)
Author(s): Boom, Milton A.
Publication: Preprint 430; Convention 17; September 1965
Abstract: Sound and communication systems for new and existing structures require analysis, specification development, equipment design and installation. Sound engineering has been called upon to satisfy one or all of these functions depending upon the system complexity and contractual arrangements with the architect and professional consultants. The relationship and responsibilities for the ultimate system performance will be illustrated with case histories involving the Arie Crown Theater, McCormick Place, Mill Run Theater and Purdue University.
	Self Induced Noise in Carbon Microphones 419838 bytes (CD aes7)
Author(s): Schiller, Elaine
Publication: Preprint 420; Convention 17; September 1965
Abstract: A characteristic of carbon microphones which is measured as noise at lower frequencies than the input signal, has been investigated at length for this paper. This phenomenon affects the transmission of speech in noise and must be taken into account when predicting intelligibility.

	332 of 9317 documents found     Page 13 of 17
	Title/Size/Author/Abstract
	Duration and/or Frequency Alteration 1111252 bytes (CD aes7)
Author(s): Marlens, William S.
Publication: Preprint 412; Convention 17; September 1965
Abstract: The control of frequency and duration independently of each other is accomplished by means of a rotary tape head. The history and principle of this device is reviewed as are the various apparatuses employing it. The ·Audulator,· the most recent of such, employs a keyboard to alter pitch over 24 chromatic steps without altering duration. The relationship of the musical scale to relative tape speed is discussed.
	The Jetarama Theater System of Airborne Entertainment 331642 bytes (CD aes7)
Author(s): Johnson, Robert E.
Publication: Preprint 409; Convention 17; September 1965
Abstract: An entertainment system consisting of motion picture and multichannel taped audio systems have been installed on 48 large jet aircraft. The solutions to the particular requirements of airborne installations and airline operation are described. Particular emphasis is placed on considerations affecting the tape and movie audio systems and distribution arrangement.
	A New Multi-Deck Broadcast Audio Tape Cartridge System 1125265 bytes (CD aes7)
Author(s): Smith II, K. Rey
Publication: Preprint 356; Convention 16; September 1964
Abstract: The KRS multiple cartridge tape system is described with emphasis on the cartridge design featuring a reversible continuous loop.
	Some Design Considerations for Short Term Audio Recording on Flexible Magnetic Sheets 402488 bytes (CD aes7)
Author(s): Skov, Erling P.; Vogel, Charles
Publication: Preprint 354; Convention 16; September 1964
Abstract: An actual sheet recorder will not be described in this paper. Instead five different design areas which deviate from those of regular reel-to-reel machines will be covered. The five areas are: 1. Head Design, 2. Head Placement, 3. Mechanical Drive System, 4. Dropouts, 5. Equalization.
	The Measurement and Minimization of Print-Through of Magnetic Sound Recording Tape 470612 bytes (CD aes7)
Author(s): Koeppe, Edward P.
Publication: Preprint 341; Convention 16; September 1964
Abstract: Print-through of magnetic sound recording tape is a problem that does exist and is affected by the time of storage, temperature, time between record and playback, external magnetic fields, the magnetic properties of the oxide used in the coating, and many other factors. A description of the recording process of magnetic print-through, various methods of measurement and the minimization of the printed signal is discussed.
	Paramike 439081 bytes (CD aes7)
Author(s): Skee, Vincent J.
Publication: Preprint 320; Convention 15; September 1963
Abstract: The evolution of an experimental high quality low noise microphone based on parametric amplifier principles. A general discussion of parametric amplifiers and results of low signal frequencies and low pump frequencies. Further discussion of high frequency type microphones in which the low-mass capacitor diaphragm controls RF signals or reactive gains of semi-conductor diodes. Performance is noted and appears to be related to capacitor microphones in the usual DC polarized forms.
	A Control Console for Multi-Speaker Presentations of Electronic Music 1847715 bytes (CD aes7)
Author(s): Mauzey, Peter
Publication: Preprint 182; Convention 13; September 1961
Abstract: In planning for the public presentation of programs of electronic music, the composers indicated a desire to experiment with a multiple loudspeaker installation. Since many signal sources would also be involved, a flexible mixing and distribution system was designed for use during experimentation and for public presentations. The mixing system incorporated in the final design will be described first followed by the circuits and measured performance of the associated amplifiers.
	Broadcasting Closed Circuit and Via Public Transmission Channels Through Master Control Facilities in the Loeb Student Center, New York University 2291839 bytes (CD aes7)
Author(s): Freitag, Werner
Publication: Preprint 157; Convention 12; September 1960
Abstract: A Communications Center to provide facilities for inter-university and to-the-public programming has been set up in one central control center in the Loeb Student Center, New York University. Broadcasting, public address systems and music appreciation facilities, including library and broadcasting instruments, are provided. Details of this communications control concept and its equipment, will be described.
	The Tape Head Relationship in Multi-Track Recording 234136 bytes (CD aes7)
Author(s): Leslie, Frazer
Publication: Preprint 117; Convention 11; September 1959
Abstract: This paper evaluates the basic tape-to-head relationship that applies in multi-track recording in comparison to that relationship in monaural operation. It studies such factors as frequency response, crosstalk, signal-to-noise ratio, distortion, and tape drop-outs, and shows that the only significant difference that occurs in multi-track recording is a small deterioration in the signal-to-noise specifications. The mechanical considerations of azimuth alignment and gap-to-gap spacing are also discussed.
	The Use of 35-mm Sprocket Type Magnetic Film in Recording Phonograph Masters 1807257 bytes (CD aes7)
Author(s): Frayne, John G.; Stafford, J. W.
Publication: Preprint 114; Convention 11; September 1959
Abstract: Although not in general use in the disk recording industry, 35-mm perforated magnetic film offers many advantages as the transfer medium from original audio signals to the final master disk recording. Its flutter, signal-to-noise ratio, modulation noise (noise behind the signal), print-through and intermodulation characteristics are excellent and, as demonstrated by its use in the motion picture industry, ease of handling and particularly editing makes it a useful recording medium. Data comparing performance characteristics to 1/4 inch tape recording will be given. Finally, as an example of 35-mm perforated magnetic film as the transfer medium in the preparation of stereo disk masters, the system used by Mr. Harry Belock at the Belock Recording Studios will be described.
	Signal Convolution of Recorded Free-Field Gunshot Wounds 3240909 bytes (CD aes6)
Author(s): Koenig, Bruce E.; Hoffman, Shawn M.; Nakasone, Hirotaka; Beck, Steven D.
Publication: Volume 46 Number 7/8 pp. 634·653; June 1998
Abstract: A field experiment was conducted using standard digital and analog recorders, telephone lines, a miniature radio-frequency transmitter-receiver system, and a video camcorder. Two pistols, two revolvers, and a shotgun were fired on an outdoor range three times each at distances of 3.05 m and 30.5 m, both toward the microphone-recorder test systems and from the side. The collected sound information was then evaluated using various methods. Excellent visual and statistical correlations were found only between the shots for the same weapon and recording device at each position. Almost all other combinations did not correlate closely with other recorded gunshot sounds. This research found specific microphones and tape recorders to respond uniquely to the high-level short duration transients of live gunshot sounds, based on position, firing direction, and the weapon and ammunition type. Good overall correlation was found between visual and statistical comparisons of the waveforms over approximately the first 10 ms. Recommendations for further research and applications to forensic examinations are set forth.
	Personal Memories of the AES in Eastern Germany and Eastern Europe 2592563 bytes (CD aes6)
Author(s): Steinke, Gerhard
Publication: Volume 46 Number 1/2 pp. 103·107; December 1997
Abstract: Not available.
	Education and the AES 2927622 bytes (CD aes6)
Author(s): Pritts, Roy
Publication: Volume 46 Number 1/2 pp. 88·90, 92; December 1997
Abstract: Not available.
	ISO/IEC MPEG-2 Advanced Audio Coding 2694783 bytes (CD aes18)
Author(s): Bosi, Marina; Brandenburg, Karlheinz; Quackenbush, Schuyler; Fielder, Louis; Akagiri, Kenzo; Fuchs, Hendrik; Dietz, Martin
Publication: Volume 45 Number 10 pp. 789·814; September 1997
Abstract: The ISO/IEC MPEG-2 advanced audio coding (AAC) system was designed to provide MPEG-2 with the best audio quality without any restrictions due to compatibility requirements. The main features of the AAC system (ISO/IEC 13818-7) are described. MPEG-2 AAC combines the coding efficiency of a high-resolution filter bank, production techniques, and Huffman coding with additional functionalities aimed to deliver very high audio quality at a variety of data rates.
	Dynamic-Range Issues in the Modern Digital Audio Environment 1960035 bytes (CD aes5)
Author(s): Fielder, Louis D.
Publication: Volume 43 Number 5 pp. 322-339; April 1995
Abstract: The peak sound levels of music performances are combined with the audibility of noise in sound reproduction circumstances to yield a dynamic-range criterion for noise-free reproduction of music. This criterion is then examined in light of limitations due to microphones, analog-to-digital conversion, digital audio storage, low-bit-rate coders, digital-to-analog conversion, and loudspeakers. A dynamic range of over 120 dB is found to be necessary in the most demanding circumstances, requiring the reproduction of sound levels of up to 129 dB SPL. Present audio systems are shown to be challenged to yield these values.
	Determining Noise Criteria for Recording Environments 1787725 bytes (CD aes5)
Author(s): Cohen, Elizabeth A.; Fielder, Louis D.
Publication: Volume 40 Number 5 pp. 384·402; April 1992
Abstract: A new noise-level criterion and measurement technique, tempered by the effect of home-listening-room noise, is used to predict the audibility of the noise levels in a number of recording facilities. It is shown that NC, PNC, or RC methods are not accurate enough in assessing noise audibility, given the high cost of creating very quiet environments.
	Corrigendum: To the Gap Loss Formula, the Asymptotic Expansion (Eq. 15a) of Westmijze's ·Studies on Magnetic Recording· 83292 bytes (CD aes5)
Author(s): McKnight, John
Publication: Volume 39 Number 11 p. 878; October 1991
Abstract: Not available.
	Digital Audio Recorders 4209131 bytes (CD aes4)
Author(s): Watkinson, John
Publication: Volume 36 Number 6 pp. 492·494, 496, 498-500, 502, 504, 506, 508; May 1988
Abstract: Once in a digital domain, audio can be stored in a wide variety of ways. This article illustrates some of the more important digital recording techniques and formats, and compares the advantages and limitations of each in terms of the functions a user might expect from a given technology.
	Subwoofer Performance for Accurate Reproduction of Music 1546477 bytes (CD aes4)
Author(s): Fielder, Louis D.; Benjamin, Eric M.
Publication: Volume 36 Number 6 pp. 443·456; May 1988
Abstract: The spectra and the maximum output levels for accurately reproducing low-frequency musical signals are determined from published research and new measurements. Analysis of commercial recordings shows substantial musical information in the octave from 32 to 16 Hz and some down to 12 Hz. Psychoacoustic data are used to establish to what degree errors (such as total harmonic distortion, FM distortion, modulation noise, and bandwidth limits) are perceptible. Criteria are set for proper subwoofer performance at peak sound pressure levels of 110 dB.
	Forensic Audio and Video·Theory and Applications 1894621 bytes (CD aes4)
Author(s): Owen, Tom
Publication: Volume 36 Number 1/2 pp. 34-41; December 1987
Abstract: The various aspects of audi and video authentication and signal processing are addressed as they apply to the introduction of such materials into evidence in the civil and criminal justice systems. The nature of these audio and video materials is usually that of surveillance tapes, which are sometimes bandwidth limited and of poor quality. Issues such as tape enhancement, signal processing, voice identification, editing or tampering, and physical degradation, which must be addressed by the forensic examiner, are discussed.

	332 of 9317 documents found     Page 14 of 17
	Title/Size/Author/Abstract
	Evaluation of the Audible Distortion and Noise Produced by Digital Audio Converters 1726895 bytes (CD aes4)
Author(s): Fielder, Louis D.
Publication: Volume 35 Number 7/8 pp. 517·535; June 1987
Abstract: A quantitative measurement technique to evaluate audible impairments caused by the noise and distortion of digital audio conversion systems is discussed and is shown to correlate well with subjective impression. Performance at low, medium, and high signal levels is examined using the auditory critical-band concept, signal masking, environmental noise making, and hearing acuity. The technique applies sine-wave signals and divides the output spectrum into auditory critical bands, which are used to determine the audibility of the noise and distortion products.
	The Audibility of Modulation Noise in Floating-Point Conversion Systems 1158469 bytes (CD aes4)
Author(s): Fielder, L. D.
Publication: Volume 33 Number 10 pp. 770·781; September 1985
Abstract: The floating-point conversion technique is particularly suited for digital audio applications where the dynamic range greatly exceeds the signal-to-noise ratio requirement for high signal levels. By adding controlled amounts of noise into the sine-wave and recorded music material, the action of various proposed systems is examined. The effects of preemphasis, various proposed systems is examined. The effects of preemphasis, various gain step sizes, and instantaneous versus near-instantaneous techniques are examined.
	History of Electronic Sound Modification 2951510 bytes (CD aes4)
Author(s): Bode, Harald
Publication: Volume 32 Number 10 pp. 730·739; September 1984
Abstract: Not available.
	Electrical Reproduction of Acoustically Recorded Cylinders and Disks 1418388 bytes (CD aes4)
Author(s): Owen, Tom
Publication: Volume 31 Number 4 pp. 266, 270, 272, 274, 275; March 1983
Abstract: Not available.
	Channel Codings for Digital Audio Recordings 1692528 bytes (CD aes4)
Author(s): Doi, Toshi T.
Publication: Volume 31 Number 4 pp. 224·238; March 1983
Abstract: Channel coding is very important in obtaining both high-density recording and high reliability. Several new channel codes have been developed for improving digital audio recording. The parameters for evaluating channel codes are described, and several conventional codes are explained with application to current systems. New codes are discussed. One new code is applied to professional recorders; another one to compact disk systems.
	Correction to "Alignment of Filter-Assisted Vented-Box Loudspeaker Systems with Enclosure Losses" 93689 bytes (CD aes4)
Author(s): Bywater, R. A. R.; Wiebell, H. J.
Publication: Volume 30 Number 9 p. 621; August 1982
Abstract: Not available.
	Correction to "Synthesis by Spectral Amplitude and 'Brightness' Matching of Analyzed Musical Instrument Tones" 93689 bytes (CD aes4)
Author(s): Beauchamp, James W.
Publication: Volume 30 Number 9 p. 621; August 1982
Abstract: Not available.
	Comments on "Examination of Audio Bandwidth Requirements for Optimum Sound Signal Transmission" 93689 bytes (CD aes4)
Author(s): Miller, Thomas E.
Publication: Volume 30 Number 9 p. 621; August 1982
Abstract: Not available.
	An Experimental "All Digital" Studio Mixing Desk 1440247 bytes (CD aes4)
Author(s): Richards, John W.; Craven, Ian
Publication: Volume 30 Number 3 pp. 117·126; February 1982
Abstract: An experimental minicomputer-based mixing desk is described in which all functions, including mixing and equalization, are implemented by real-time digital signal processing hardware. The experimental mixer has 16 input channels, 8 track outputs, and full monitoring and auxiliary facilities. The equipment was first used operationally during experimental recording sessions in late 1979, and since mid 1980 it has been undergoing extended operational trials.
	Maintenance Procedures for Ferrite Heads 2913850 bytes (CD aes4)
Author(s): Manquen, C. Dale; Martinson, Joe
Publication: Volume 27 Number 11 pp. 881·886; October 1979
Abstract: Despite manufacturers' claims to the contrary, ferrite heads do manifest unique problems that require routine maintenance procedures. Microscope photographs and performance data for typical ferrite heads on mastering recorders are presented with recommendations for specific periodic tests to detect gap erosion.
	How the Magnetic Characteristics of a Magnetic Tape Head Are Affected by the Gap Length and a Conducting Spacer 541657 bytes (CD aes4)
Author(s): McKnight, John G.
Publication: Volume 26 Number 12 pp. 930·934; November 1978
Abstract: Eleven graphs show head efficiency versus gap length, complex permeance spectra, and modulus of efficiency spectra from 1000 Hz to 16 MHz for heads with gap lengths of 0.4 µm, 4 µm, 12 µm, and 50 µm, with conducting and with nonconducting gap spacers. Several optimization questions are also posed.
	On the Need for a Standard Method for Primary Calibration of the Frequency and Wavelength Response of a Magnetic Tape Reproducer 363219 bytes (CD aes4)
Author(s): McKnight, John G.
Publication: Volume 26 Number 11 pp. 867·870; October 1978
Abstract: Not available.
	The Musician and the Record 498802 bytes (CD aes3)
Author(s): Torick, Emil L.
Publication: Volume 25 Number 10/11 pp. 880·884; September 1977
Abstract: The response of the musician to the introduction, growth and maturity of recorded sound is reviewed. As the technology evolved, the musician's fears of unemployment due to automation were eventually realized. Following the subsequent turbulent period which has severe impact on the musician, the recording industry and the public alike, an accommodation has been reached which appears to be satisfactory to all.
	Electronic Music 1399523 bytes (CD aes3)
Author(s): Moog, Robert A.
Publication: Volume 25 Number 10/11 pp. 855·861; September 1977
Abstract: Not available.
	A Method for Measuring Transient Intermodulation Distortion 830320 bytes (CD aes3)
Author(s): Leinonen, Eero; Otala, Matti; Curl, John
Publication: Volume 25 Number 4 pp. 170·177; March 1977
Abstract: A description of the square-sine intermodulation measuring method is given. The practical measuring procedure is described, and measurement results of commercial audio power amplifiers and integrated operational amplifiers are presented, in many cases showing appreciable transient intermodulation in units which have excellent and total harmonic distortion and SMPTE intermodulation distortion specifications. The correlation of these measurements with results obtained using other methods, such as the CCIF-IM and the noise-transfer method, is treated, and the interdependence of these with the slew rate and the power bandwidth is discussed.
	·Transistors Can Sound Better Than Tubes· and ·Comments on `Transistors Can Sound Better Than Tubes'· 798930 bytes (CD aes3)
Author(s): Monteith, Jr., Dwight O.; Flowers, Richard R.; Hamm, Russell O.
Publication: Volume 25 Number 3 pp. 116·120; February 1977
Abstract: A design for a high-voltage preamplifier is presented in response to the debate taking place on the question of tube sound versus transistor sound. This design combines a low-noise input transistor with high-voltage output transistors to give noise performance comparable to an LM 381 and the large signal capability of tube circuits. When severely overloaded, this preamplifier producer harmonic distortion components which are comparable to, and perhaps more pleasing than, tube preamplifiers.
	Magnetic-Head Relapping Techniques 331557 bytes (CD aes3)
Author(s): Dundovic, Joseph F.
Publication: Volume 24 Number 8 pp. 656·659; September 1976
Abstract: Not available.
	Motion Picture Sound Recording 994273 bytes (CD aes3)
Author(s): Frayne, John G.
Publication: Volume 24 Number 6 pp. 512-516; June 1976
Abstract: Not available.
	A Study of Time-Domain Speech Compression by Means of a New Analog Speech Processor 853581 bytes (CD aes3)
Author(s): Bennett, I. M.; Linvill, J. G.
Publication: Volume 23 Number 9 pp. 713·721; October 1975
Abstract: Time-domain speech compression using the SDA (sample, discard, abut) procedure at compression ratios of 0.25 to 0.75 is studied by means of a new analog speech processor and minicomputer algorithms. Fourier transform methods have been used to establish a correspondence between the quality of the reconstructed compressed speech waveforms and the subjective recognition of compressed speech. The result of two psychoacoustic experiments indicate that 1) the interruption frequency should be equal to the pitch frequency of the voice waveform for optimum recognition of the compressed speech, and 2) smoothing of the discontinuities with electronic techniques significantly improves the recognition of the compressed speech. The optimum smoothing parameters, window width and characteristic function, are also obtained from this study.
	NQRC Measurement of Subjective Aspects of Quadraphonic Sound Reproduction·Part 2 327780 bytes (CD aes3)
Author(s): Woodward, J. G.
Publication: Volume 23 Number 2 pp. 128·130; February 1975
Abstract: A series of listening tests conducted by Panel 6 of the National Quadraphonic Radio Committee (NQRC) measured auditors' preferences for music reproduced by 4·4·4, 4·3·4, and 4·2·4 quadraphonic encode/decode systems. These quadraphonic systems are ranked in terms of auditor preference. This ranking correlates closely with the ranking based on localization tests as reported in Part 1.

	332 of 9317 documents found     Page 15 of 17
	Title/Size/Author/Abstract
	Reply to Messrs. Wilson and Wilson: A Commentary on Audio Education and Percy Wilson 140343 bytes (CD aes3)
Author(s): Moverman, Paul S.
Publication: Volume 22 Number 2 p. 103; February 1974
Abstract: Not available.
	A Method for Qualifying Recorded Tone Bursts 1521524 bytes (CD aes3)
Author(s): Blethen, William M.
Publication: Volume 21 Number 5 pp. 387-392; May 1973
Abstract: A circuit philosophy is described for qualifying properly recorded tone bursts on tape recordings. More specifically, these bursts, recorded on a control track accompanying audio materials, are used to synchronize various events in a low-cost audio visual machine. The circuit checks three important parameters of each burst; amplitude, duration, and frequency, and displays the total of all correct bursts. A block diagram and design philosophy are covered.
	Sound of the Games 3322086 bytes (CD aes3)
Author(s): Roizen, Donna; Roizen, Joseph
Publication: Volume 21 Number 5 pp. 381·387; May 1973
Abstract: Sound coverage for a modern athletic event is a complex and expensive undertaking. The demand of local sound reinforcement and instantaneous audio reporting on radio and television required an array of equipment unmatched by other public events. The 20th Olympiad in Munich, which ranked as the largest communications event of the century to date, also included the most comprehensive audio system ever assembled. The three aspects of audio coverage are described.
	Tubes Versus Transistors·Is There an Audible Difference 731921 bytes (CD aes3)
Author(s): Hamm, Russell O.
Publication: Volume 21 Number 4 pp. 267·273; April 1973
Abstract: Engineers and musicians have long debated the question of tube sound versus transistor sound. Previous attempts to measure this difference have always assumed linear operation of the test amplifier. This conventional method of frequency response, distortion, and noise measurement has shown that no significant difference exists. This paper, however, points out that amplifiers are often severely overloaded by signal transients (THD 30%). Under this condition there is a major difference in the harmonic distortion components of the amplified signal, with tubes, transistors, and operational amplifiers separating into distinct groups.
	A Study to Establish Optimum Level on Cassette Tape Copies 371100 bytes (CD aes3)
Author(s): Smith, Stewart L.; Wood, James B.
Publication: Volume 21 Number 1 pp. 42, 45, 46, 48; December 1972
Abstract: The higher noise level associated with cassettes makes the selection of a recorded program level more critical in this format to obtain an optimum compromise between noise and distortion. The various phases of a study undertaken to establish program levels for duplicated cassette copies based on program peak level information are described. The design of an automatic program peak level accumulator is discussed as are final results of the study.
	Production of Dolby B-Type Cassettes 1315161 bytes (CD aes3)
Author(s): Robinson, D. P.
Publication: Volume 20 Number 10 pp. 835·841; November 1972
Abstract: The compact cassette has now reached a point in its development at which it deserves serious consideration as a quality music medium. An essential contribution to this improved quality is the use of the Dolby B-type noise reduction system. The cassette duplication process is outlined with particular reference to achievable signal-to-noise ratios, distortion characteristics, high and low frequency equalization, and choice of bias frequencies. A professional Dolby B-type encoder is described, together with its use in the duplicating chain. Standardization and quality control procedures are discussed, and examples are given of B-type encoded cassette identification.
	The Fringing Response of Magnetic Reproducers at Long Wavelengths 504236 bytes (CD aes3)
Author(s): McKnight, J. G.
Publication: Volume 20 Number 2 pp. 100-105; February 1972
Abstract: When a recorded track is wider than the reproducing head, the apparent tape flux at long wavelengths is increased. This produces a boost in low-frequency response, and a measuring error in the ·level set· and the frequency response of a multitrack reproducer playing a full-track test tape. Normalized graphs (based on Grimwood's formula) are given which show the appropriate level corrections for fringing in common reproducing systems.
	An Electronically Generated Complex Microtonal System of Horizontal and Vertical Tonality 917419 bytes (CD aes3)
Author(s): Goldsmith, David S.
Publication: Volume 19 Number 10 pp. 851·858; October 1971
Abstract: The possibility for chordal tonality as an organizing principle for aperiodic tones is demonstrated. Such tones can be quite useful musically, for they sound richer than sinusoids and still permit certain stable intervallic structures among themselves that would not be present were complex periodic tones used instead of these structures. A novel microtonal tuning model that supports a new horizontal and vertical or chordal tonality is extrapolated from Pierce [1]. Since stability of novel intervallic structures is largely partial format dependent and is basic to harmonic function and to vertical tonality, electronic tone generation, because it makes possible these novel stable structures, permits the production of horizontal and vertical tonalities with novel intervals that function in a form-building and orienting way equivalent to traditional harmonic tonality but with a different sound. The model suggests that traditional harmonic tonality is that vertical as well as horizontal tonality which is promoted by the use of periodic and quasiperiodic tones. Embodiment of such new tonal systems in relatively inexpensive special-purpose or dedicated electrophonic keyboard instruments is recommended.
	Subjective Assessment of Multichannel Reproduction 959083 bytes (CD aes3)
Author(s): Nakayama, Takeshi; Miura, Tanetoshi; Kosaka, Osamu; Okamoto, Michio; Shiga, Takeo
Publication: Volume 19 Number 9 pp. 744·751; September 1971
Abstract: Subjective effects of one- through eight-channel reproductions were studied. Two popular musical selections were played at the Beethoven Hall of Musashino Music College and recorded using an eight-channel tape recorder. One- through eight-channel reproductions were made in an anechoic chamber. Preference judgements of each reproduction and similarity judgements among them were made by ten listeners. As a result of multidimensional analysis of the similarity data, it is found that the multichannel recording and reproduction of music from such an acoustical setting is characterized by three sensory features: fullness, clearness, and depth of the image sources. Of these, fullness has the greatest weight in determining preferences among the reproduced sounds. Relations among the three sensory features and between these and the physical characteristics of recording and reproducing sound fields are discussed. The depth of the image sources is found to be a function of the front speaker angle, and the clearness a function of the definition (Deutlichkeit). The close relationship between the fullness and a small value for the cross-correlation coefficient between sounds at the listener's ears (incoherence) is also suggested.
	A Simplified Hysteresis-Loop Model of the AC-Biased Magnetic Recording Process 720320 bytes (CD aes3)
Author(s): Vajda, Zoltan
Publication: Volume 19 Number 5 pp. 398·404; April 1971
Abstract: The model described in the paper is based on the assumption that the remanence of a magnetic material exposed to a series of field maxima of alternating sign, can be calculated as the superposition of the magnetizations, brought about by the successive maxima. Using a straight line approximation for the magnetization vs. field function, results in a theoretical recording model free of material-induced losses and distortion. By this model the influence of the recording geometry on the recorded signal smplitude and waveform can be examined. Recording, demagnetization, wavelength dependent harmonic distortion and phase shift data, calculated by computer, are displayed, and the limitations of this particular model, and those of the so-called `classical' recording models are compared and discussed.
	Comments on "Biradial and Spherical Stylus Performance in a Broadcast Disc Reproducer" and Author's Reply 189858 bytes (CD aes3)
Author(s): Barlow, D. A.; Sank, J. R.
Publication: Volume 19 Number 2 pp. 145, 146; January 1971
Abstract: Not available.
	Subjective or Psophometric Audio Noise Measurement: A Review of Standards 686917 bytes (CD aes3)
Author(s): Wilms, Herman A. O.
Publication: Volume 18 Number 6 pp. 651·656; November 1970
Abstract: Dynamic ranges (in dB) are meaningless if the noise measurement method is not specified. A survey is given of the CCITT, DIN, IEC, and the new CCIR standards on the psophometric measurement of audio noise. Differences in the dynamic properties and the weighting filters are discussed. Measurement of an audio noise with different weighting filters gives different values; these results are computed for a white-noise (constant density) spectrum and a red-noise (density ·6 dB per octave) spectrum.
	Calculation of the Stray Reluctance of Gaps in Magnetic Circuits 293406 bytes (CD aes3)
Author(s): Unger, Egon; Fritzsch, Klaus
Publication: Volume 18 Number 6 pp. 641·643; November 1970
Abstract: For determining the reluctance of gaps in magnetic circuits, an approximation method is suggested which is deduced from an exact calculation. It is demonstrated that the contribution of the stray field to the total reluctance is proportional to the reciprocal of the logarithm of the ratio between the maximum length of the stray-field lines and the gap length.
	The Dynamic Range of Disc and Tape Records 694244 bytes (CD aes3)
Author(s): Gravereaux, Daniel W.; Gust, Arthur J.; Bauer, Benjamin B.
Publication: Volume 18 Number 5 pp. 530·535; September 1970
Abstract: The emergence of the tape cartridge and cassette as entertainment media prompts comparisons with the disc record. Factors which control the disc noise during production have been measured and are discussed and the geometric level limitation of a disc, occurring in an equalized player, is described. Both the level capability and the background noise of cartridge and cassette tape are measured and discussed. The dynamic range curves of each medium are compared by referencing to the audible background noise and examining the level capability. At present the disc record has the greater dynamic range.
	Performance Characteristics of the Commercial Stereo Disc 653882 bytes (CD aes3)
Author(s): Eargle, John
Publication: Volume 17 Number 4 pp. 416·422; July 1969
Abstract: The study examines the state of the art in processing master lacquers through the intermediate stages of metal plating on through to vinyl pressing. Detailed noise and distortion measurements at each interface are described, and the effects of normal variations in processes as well as changes in materials are noted.
	High-Density Disc Recording Systems 308372 bytes (CD aes3)
Author(s): Levens, Leo M.
Publication: Volume 17 Number 3 pp. 309·311; May 1969
Abstract: Continuing investigation in the field of high-density disc recording has resulted in a 4 1/6 rpm record with a playing time of 20 hours. Some of the history and reasoning underlying this development is presented, description of the processes and elements of the system is given, and the potential of the system is assessed.
	The Loudness Balance of Audio Broadcast Programs 375436 bytes (CD aes3)
Author(s): Belger, Ernst
Publication: Volume 17 Number 3 pp. 282·285; May 1969
Abstract: Some studies are reviewed showing that the desired loudness balance between speech and music in audio broadcasts is influenced by the type of program, the age and sex of the listener, and various other factors, and that the requirements of various groups of listeners are often contradictory. The possibility of automatic balance monitoring is examined, and a device for automatic discrimination between speech and music is outlined.
	Compatibility of Stereo Recordings and Monaural Playback 502236 bytes (CD aes3)
Author(s): Sobel, I. J.; Knuebel, Ronald
Publication: Volume 17 Number 2 pp. 143·146, 240; March 1969
Abstract: The decreasing availability of monaural recordings has raised the important question of the compatibility of the stereo recording when played back with one of the monaural pickup cartridges in current use. Some quantitative data are presented showing the effect on stereo recordings of several monaural cartridges requiring a range of vertical tracking force. The results show a rather wide range of effects from minimal wear with high-compliance pickups to very rapid deterioration when stereophonic recordings are reproduced with a low-compliance cartridge requiring heavy tracking force.
	An Improved Automatic Level-Control Device 601882 bytes (CD aes3)
Author(s): Aiken, William Ross; Swisher, Charles F.
Publication: Volume 16 Number 4 pp. 447·449; September 1968
Abstract: A highly refined lamp-photocell automatic level control device is described which has fast attack time, instantaneous transient release and low distortion. The device is based on a compressor/limiter circuit which provides the advantages of conventional lamp-photocell operation but has been modified to eliminate the concomitant disadvantages.
	Comments on: "Hand Relapping of Tape Heads" 853572 bytes (CD aes3)
Author(s): Moura, Carlos E. R. A.
Publication: Volume 16 Number 3 pp. 356, 358, 360, 362; June 1968
Abstract: Not available.

	332 of 9317 documents found     Page 16 of 17
	Title/Size/Author/Abstract
	Comments on "·Phase Compensation in Tape Copying·" 505735 bytes (CD aes3)
Author(s): Tall, Joel
Publication: Volume 16 Number 3 pp. 362, 364; June 1968
Abstract: Not available.
	Synchronous Sound for Motion Pictures 492705 bytes (CD aes3)
Author(s): Ryder, Loren L.
Publication: Volume 16 Number 3 pp. 291·295; June 1968
Abstract: The synchronization of sound with motion pictures, an important concern of motion picture and videotape producers, is examined. The several methods normally used in handling and retaining sound synchronization from the original camera shooting to the final projection are described and their relative advantages and disadvantages discussed.
	Filtering RF Interference in Audio Equipment 379146 bytes (CD aes3)
Author(s): MacCollister, R. S.
Publication: Volume 16 Number 2 pp. 210, 212, 214; March 1968
Abstract: Not available.
	A Brief Review of EIA Standards in the Audio Field 518309 bytes (CD aes3)
Author(s): Caffiaux, J. A.
Publication: Volume 16 Number 1 pp. 21·25; December 1967
Abstract: This paper presents some background information on EIA, its Engineering Department, and its standardization procedures. It then identifies twenty-five EIA Standards relating to the audio field in such categories as broadcasting, sound systems, loudspeakers, pickups, styli, phones, disc and magnetic recording and power output ratings. The content of some of the more widely used of these standards is described, as well as new standards efforts under development.
	Higher Speed Duplication of Eight-Track Tapes with Enhanced Dynamic Range 1718689 bytes (CD aes2)
Author(s): Johnson, Keith O.; Nelson, Carl S.
Publication: Volume 15 Number 1 pp. 11·15; December 1966
Abstract: A nearly ideal focused gap field recording technique greatly reduces the problems associated with the lower speeds of the eight-track prerecorded tape cartridges for automotive use. Use of the technique essentially eliminates bias noise, reduces bias erasure or self-demagnetization loss of high frequencies to levels approaching thosse of unbiased recording, and causes only negligible amounts of thickness distortion. The technique is described and its use in ultra-high-speed duplicating equipment is explained.
	Duration and Frequency Alteration 2686173 bytes (CD aes2)
Author(s): Marlens, William S.
Publication: Volume 14 Number 2 pp. 132·139; March 1966
Abstract: The control of frequency and duration independently of each other is accomplished by means of a rotary tape head. The history and principle of this device are reviewed, as are the various apparatuses employing it. The Audulator, the most recent of such devices, uses a keyboard to alter pitch over 24 chromatic steps without altering duration. The relationship of the musical scale to relative tape speed is discussed.
	The New NAB Tape Standards 811217 bytes (CD aes2)
Author(s): Bartlett, George
Publication: Volume 13 Number 3 pp. 248-252; June 1965
Abstract: Not available.
	Intensities of Orchestral Instrument Scales Played at Prescribed Dynamic Markings 726333 bytes (CD aes2)
Author(s): Clark, Melville; Luce, David
Publication: Volume 13 Number 2 pp. 151·157; March 1965
Abstract: The intensities of scales played on nonpercussive orchestral instruments at various dynamic markings and the resulting dynamic ranges are reported. We are able to deduce the size of quanta corresponding to one step in a dynamic marking and the numer of quanta in the dynamic range of a musical instrument using deviations from smoothed curves. The average dynamic range of the nonpercussive orchestral instruments is about 11 db between the dynamic markings of pianissimo and fortissimo; the average intensity level at 10 meters is about 59 db re 0.0002 dynes/cm/2.
	An Integrated Electronic Music Console 2508899 bytes (CD aes2)
Author(s): Hiller, Jr., L. A.
Publication: Volume 13 Number 2 pp. 142·150; March 1965
Abstract: A compact but complete electronic music apparatus has been built for the Experimental Music Studio at the University of Illinois. This apparatus incorporate signal generators, signal modifiers, analytical and test equipment, recording equipment and a central console and work area where the operation of the whole assembly is organized and controlled. The apparatus is operated very easily in either two-channel stereophonic or monophonic modes.
	A New Multi-Deck Broadcast Audio Tape Cartridge System 780538 bytes (CD aes2)
Author(s): Smith II, K. Rey
Publication: Volume 12 Number 4 pp. 327·329; September 1964
Abstract: A novel multiple cartridge tape system is described, with emphasis on the cartridge design featuring a reversible continuous loop.
	A Successful Re-Slitter for Magnetic Tape 546159 bytes (CD aes2)
Author(s): Prout, James H.
Publication: Volume 12 Number 3 pp. 258,260; June 1964
Abstract: The desire to re-slit wide magnetic tape into 1/2-inch or 1/4-inch widths is frequently expressed. Usually the quantities involved are insufficient to warrant an elaborate device and simple devices fail to produce satisfactory results; however a large supply of 3/4-inch instrumentation tape supplied the author with an incentive for a serious effort to design a re-slitter to convert this into 1/2-inch wide tape. This paper describes the design and operation of the re-slitter. Width variations were held to ±0005 inch, well within instrumentation tolerances. A drop-out check showed the tape to be satisfactory for re-use as instrumentation tape.
	Preliminary Experiments on the Aural Significance of Parts of Tones of Orchestral Instruments and on Choral Tones 839311 bytes (CD aes2)
Author(s): Clark, Jr., Melville; Luce, David; Abrams, Robert; Schlossberg, Howard; Rome, James
Publication: Volume 11 Number 1 pp. 45·54; December 1962
Abstract: In a series of preliminary experiments we found that the attack transient is quite important in the aural identification of a nonpercussive instrument of the orchestra as compared with the steady state or the decay transient. The ·attack transients· of percussive instruments are of very little significance for their identification. The circuits for several quiet gates which we developed are presented. The widths of the distributions and the number of partials are of aural significance in choral tones; the differences between the few laws of spacing that we studied seem relatively unimportant. Choral tones with widths of ±1 percent can be distinguished from solo tones for durations as short as 0.03 second.
	Control Console for Multi-Speaker Presentations of Electronic Music 1409319 bytes (CD aes2)
Author(s): Mauzey, Peter
Publication: Volume 10 Number 4 pp. 338, 339, 342, 344, 346, 348; September 1962
Abstract: Not available.
	A Method of Testing Loudspeakers with Random Noise Input 419980 bytes (CD aes2)
Author(s): Villchur, Edgar
Publication: Volume 10 Number 4 pp. 306·309; September 1962
Abstract: Not available.
	An Investigation of Speed Variations in a Magnetic Tape Recorder, with the Aid of Electro-Mechanical Analogies 1231905 bytes (CD aes2)
Author(s): Wolf, W.
Publication: Volume 10 Number 2 pp. 119·129; March 1962
Abstract: The electrical analog of a tape transport is derived, as well as means for converting mechanical values to and fron analogous electrical values. The values of the mechanical elements are determined, in some cases with the aid of their electrical analogs. The response of the mechanical system is analyzed through its electrical analog, and recommendations are made for improving the transport design.
	The Transmission of Room Information 427057 bytes (CD aes2)
Author(s): Wendt, Klaus
Publication: Volume 9 Number 4 pp. 282·283, 318, 320; September 1961
Abstract: The acoustical properties of a closed room influence the development in time and space of the sound pressure that is caused by the occurrence of a sound in the room. The time function originated by the sound source thus acquires, on its way to the listener, additional information concerning the room in which the sound takes place, and this the author called the room information. With electroacoustical transmission, the room information may be made audible in the listening room by way of its own channel. Measurements of the optimum loudnsess of the room information transmitted indicate that it is a function of the size and reverberation-time of the originating room.
	The Reduction of Wind Noise in Microphones 245073 bytes (CD aes2)
Author(s): Burroughs, L. R.
Publication: Volume 9 Number 2 pp. 168,170; March 1961
Abstract: Not available.
	Acoustic Instrumentation for Measurements in the Minuteman Missile Silo 521259 bytes (CD aes2)
Author(s): Keast, David N.; Kamperman, George W.
Publication: Volume 8 Number 3 pp. 180·184; June 1960
Abstract: An instrumentation system has been developed to measure, record, and analyze various properties of the dynamic pressure field in the Minuteman launching silo. This system permits the simultaneous recording of up to 13 channels of data from microphones placed in the silo environment. These data may then be processed to obtain frequency spectra, time correlation functions, and space correlation functions. The data acquisition system has a frequency response from 0 to 10,000 cps, a wide dynamic range, and (to permit correlation analyses) a maximum channel-to-channel phase difference of 10°. Various system design problems are discussed. These include the choice of transducers to function in the high-temperature high-vibration environment of the silo, the equalization of phase shift between the data channels, and the phase matching of filters for space correlation. Representative samples of data obtained with the system are used for illustration.
	The Use of 35-mm Sprocket-Type Magnetic Film in Recording Phonograph Masters 1595525 bytes (CD aes2)
Author(s): Frayne, John G.; Stafford, J. W.
Publication: Volume 8 Number 3 pp. 172·176; June 1960
Abstract: This paper discusses the use of perforated 35-mm magnetic film as the recording medium in preparing phonograph masters; the Westrex 35-mm system is described. Performance characteristics are given. A comparison of 35-mm magnetic film versus 1/4-in. magnetic tape relative to flutter, signal-to-noise ratio, print-through, modulation noise, and intermodulation distortion is given.
	Synthetic Reverberator 1189484 bytes (CD aes2)
Author(s): Olson, Harry F.; Bleazey, John C.
Publication: Volume 8 Number 1 pp. 37·41; December 1959
Abstract: The reproduction of sound may be enhanced by the addition of artificial reverberation when the reproduced sound is below the optimum value of reverberation. Reverberation consists of multiple reflections in which each pencil of sound suffers a decrease in intensity with each reflection. This may be simulated by passing the reproduced sound through a series of transducers with progressive delay and attenuation. A synthetic reverberator has been developed with a loudspeaker, pipe, and microphone delay unit in combination with a feedback system.

	332 of 9317 documents found     Page 17 of 17
	Title/Size/Author/Abstract
	A Survey of Some New Tubes for Audio Output Applications 301957 bytes (CD aes2)
Author(s): Moe, Robert E.
Publication: Volume 8 Number 1 pp. 34·36; December 1959
Abstract: Four recently announced pentodes and two rectifiers, covering the range of 14- to 60-w push-pull output, are discussed along with analysis of operating conditions, performance, and circuit design precautions. Discussion of safety factors on overload versus published ratings is also given.
	Applying the Transistor in a Stereophonic Tape System 726317 bytes (CD aes2)
Author(s): Jones, Dwight V.
Publication: Volume 7 Number 3 pp. 133·134, 140; June 1959
Abstract: A complete semiconductor, stereophonic tape playback system applies modern solid state devices to a new concept of music appreciation that is receiving more interest every day. This system consists of a stereophonic tape deck, two tape preamplifiers, two 10-watt amplifiers, two 16-ohm speaker systems, and a common power supply. Transistors offer many advantages in high fidelity circuits, since there is no problem with microphonics or hum pick-up from filaments as we have with tubes. Transistors are inherently low impedance devices and thus offer better matching to magnetic pick-ups and loud speakers, for more efficient power transfer.
	The Deformation of Plastics with Hard, Spherical Indentors 412291 bytes (CD aes2)
Author(s): Flom, D. G.; Huggins, C. M.
Publication: Volume 7 Number 3 pp. 122·124, 128; June 1959
Abstract: The response of plastics to stress when deformed by contact with hard objects under load is important in such diverse applications as bearings, guides, and phonograph records. A study of the permanent deformation of Plexiglas by spherical indentors under a wide range of load, indentor diameter, and time of loading has shown that a single relationship can be used to relate these and other variables. Preliminary sliding experiments at extremely low speeds (ca. 10/-5 cm/sec) indicate that the relationship derived for static indentations can be used to predict the permanent deformation to be expected in sliding under conditions of diverse loads and speeds. A particularly valuable application is that of predicting the deformation properties of proposed phonograph record systems by comparison with the known properties of existing systems.
	Journal Authors, Volume 3, Number 3 277534 bytes (CD aes2)
Author(s): Snyder, Ross H.
Publication: Volume 3 Number 3 pp. 167, 168; June 1955
Abstract: Not available.
	Practical Tape Duplication 1688613 bytes (CD aes2)
Author(s): Snyder, Ross H.
Publication: Volume 3 Number 3 pp. 160-165; June 1955
Abstract: Design considerations affecting the manufacture of a tape-duplicating apparatus are presented. These include acceptable signal-to-noise ratio, frequency response, distortion, and timing stability. Alternative desirable operating methods are considered. The high-speed production of a relatively small number of copies from each one of a large number of master tapes calls for very different apparatus from that required for the production of large numbers of copies from a relatively small number of master tapes. A reasonable compromise with both operating methods is proposed. The problem of equalization is dealt with.
	Measurement of Flutter and Wow in Magnetic-Tape Instrumentation Recorders 348977 bytes (CD aes2)
Author(s): Mullin, John T.
Publication: Volume 3 Number 3 pp. 151·154; June 1955
Abstract: Specifications for all tape recorders for professional and instrumentation applications include performance figures with regard to flutter and wow. Techniques of measurement give divergent results. The method employed in the author's organization is described, and a comparison is made of results obtained by this method and other methods of less precision.
	Journal Authors, Volume 2, Number 1 409254 bytes (CD aes2)
Author(s): Kelly, Jr., Arthur W.
Publication: Volume 2 Number 1 pp. 63-64; December 1953
Abstract: Not available.
	Multichannel Sound Reproduction 1861414 bytes (CD aes2)
Author(s): Selsted, Walter T.
Publication: Volume 2 Number 1 pp. 20·24; December 1953
Abstract: Not available.
	Journal Authors, Volume 1, Number 4 559915 bytes (CD aes2)
Author(s): Minter, Jerry B.; Miccioli, Aldo R.
Publication: Volume 1 Number 4 pp. 331-333; September 1953
Abstract: Not available.
	A Low-Noise FM Recording System 304256 bytes (CD aes2)
Author(s): Selsted, Walter T.
Publication: Volume 1 Number 2 pp. 213·215; March 1953
Abstract: This paper describes the use of FM carrier techniques in magnetic tape recording for the purpose of improving the overall signal-to-noise ratio of a magnetic recording system. The system to be described has been demonstrated to have appreciably better than 70-db signal-to-noise ratio relative to a distortion level of 1%.
	History and Development of Stereophonic Sound Recording 1078564 bytes (CD aes2)
Author(s): Snyder, Ross H.
Publication: Volume 1 Number 2 pp. 176·179; March 1953
Abstract: The pioneering work on stereophonic reproduction by Dr. Fletcher and the Bell Laboratories is described. Consideration is given to the relative importance of frequency range, noise, and distortion in monaural vs multichannel reproduction. Distinction is made between binaural and stereophonic reproduction. Thge realization in practical form of the requirements laid down by early research through the use of magnetic tape recording is described. Phase relations are analyzed and requirements for the preservation of three-dimensional effect are defined.
	A New Professional Magnetic Recording Tape 1683436 bytes (CD aes2)
Author(s): Schmidt, Edward
Publication: Volume 1 Number 1 pp. 10·16; December 1952
Abstract: A review of the desired properties for a professional magnetic tape indicates that increased output at constant distortion, better and more consistent hi response, and a smoother coated surface would be welcomed features. In addition, certain applications present requirements for an alternate base having additional long-term storage facility and greatly improved shrink and swell factors. This paper will present data and describe production methods used in the manufacture of a new professional tape now available on two types of base supports.