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Journal of the Acoustical Society of America

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Jul 1936

Volume 8, Issue 1, pp. 1-69

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Psychophysiological Acoustics: Pitch and Loudness

S. S. Stevens and H. Davis

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 1-13 (1936); (13 pages) | Cited 2 times

Online Publication Date: 15 Jun 2005

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The problem of psychophysiological acoustics is to determine the characteristics of auditory sensation in terms of the physical dimensions of the stimulus and the relation of physiological phenomena (in animals) to the same stimuli, and by comparison to infer the relation of the psychological function to the physiological. Four such correlations have been examined. (1) Data previously reported show a fairly good correspondence of the threshold function of electric response and the psychological thresholds. (2) Pitch perception depends upon selective resonance of different portions of the basilar membrane, although an intense tone activates a large area. The positions of maximal sensitivity were determined by the effect of localized lesions of the cochlea upon the threshold for electric response. The resulting map was compared with the map derived from the integration of Shower and Biddulph's data on pitch discrimination. The correspondence is very close (Fig. 1). (3) The equal loudness contours of Fletcher and Munson were compared with the corresponding contours of intensity required to produce equal electric responses from the cochlea. The correspondence is satisfactory. (4) The loudness function of Churcher was compared with the relation between the intensity of a 1000‐cycle tone and the magnitude of the electric response of the cochlea. The functions are similar as a first approximation, except at high intensities. The deviations are partly random, partly systematic. Theoretical explanations of the deviations are suggested. The size of the electric response of the auditory nerve, representing the total number of active fibers, also corresponds approximately to the loudness function. The loudness function does not correspond to the function obtained by integration of the difference limens for loudness (data of Riesz). A DL at high intensity involves the addition of more loudness and therefore the activation of more nerve fibers than a DL at low intensity. As a first approximation, the size of a DL in sones (units of loudness) is expressed by DL  =  KN1.2, where N is the number of DL′s above threshold.

Change of Pitch with Loudness at Low Frequencies

William B. Snow

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 14-19 (1936); (6 pages)

Online Publication Date: 15 Jun 2005

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The changes in pitch which result from changes in the loudness of low frequency tones were investigated for several frequencies between 75 and 1000 c.p.s. with a crew of 9 observers. The loudness levels covered the range 20 to 120, and both telephone receivers and a loudspeaker were used as sound sources. Fletcher's pitch standard, a pure tone of loudness level 40, was employed. All consistent judgments gave pitch shifts downward with increasing loudness, but large differences between individuals were found. Two observers perceived no shifts at any frequency or loudness while three others experienced changes greater than 35 percent at the highest intensity. Appreciable changes with time in individual judgments were found. There appeared insignificant difference between data obtained with telephone receivers or with the loudspeaker. A set of contours of equal loudness level, plotted on coordinates frequency and pitch change in percent, is given. These curves show a pitch change small at 1000 cycles, increasing to maximum at a low frequency and decreasing for still lower frequencies. The frequency of greatest shift increased from about 100 cycles at small loudness to about 200 at loudness level 120. The Appendix describes automatic test equipment that greatly simplified the testing routine and improved its accuracy.

The Influence of Intensity on the Pitch of Violin and 'Cello Tones

Don Lewis and Milton Cowan

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 20-22 (1936); (3 pages)

Online Publication Date: 15 Jun 2005

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Certain Subjective Phenomena Accompanying a Frequency Vibrato

Winston E. Koch

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 23-25 (1936); (3 pages)

Online Publication Date: 15 Jun 2005

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Sonic Marker Beacon for Fog Aviation

Chester W. Rice

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 26-29 (1936); (4 pages)

Online Publication Date: 15 Jun 2005

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The Sonic Locator

Chester W. Rice

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 30-33 (1936); (4 pages)

Online Publication Date: 15 Jun 2005

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Apparatus and Technique for Reverberation Measurements

Frederick V. Hunt

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 34-41 (1936); (8 pages) | Cited 1 time

Online Publication Date: 15 Jun 2005

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The conventional method of timing sound decay to an adjustable threshold is made automatic by a system of relays which control the following sequence: When a predetermined sound level is attained in the chamber the source is turned off and an electric timer is started: when the sound level falls to the adjustable threshold the timer is stopped and the source is turned on again. This recurrent cycle is stopped after ten repetitions and the average time for a single decay may be read directly from the timer. The apparatus is entirely a.c.‐operated and 80 db of decay can be recorded in the middle audiofrequency range. It is found that a low‐pass electric wave filter can be used to eliminate the rapid fluctuations in the rectified output of the microphone amplifier without altering the recorded decay rate. This artifice, in conjunction with the warble tone, is capable of reducing the deviations from smoothness in the decay curves to a value comparable with the random timing error without resorting to rotating vanes in the sound chamber. A statistical analysis of the residual timing errors is given.

Filtration of Elastic Waves in Solid Rods with Membranes as Side Branches

R. B. Lindsay and T. G. Barnes

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 42-47 (1936); (6 pages) | Cited 1 time

Online Publication Date: 15 Jun 2005

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This paper considers theoretically the propagation of compressional and torsional waves in solid rods having membranes as side branches. An infinite cylindrical rod is loaded at equal intervals with flexible circular membranes attached at their outer edges to the inside of a circular cylinder (see Fig. 1). The assumption that longitudinal waves in the rod set up symmetrical transverse waves in the membranes leads to the conclusion that the structure is a high‐pass compressional wave filter. The limiting case of an infinitely rigid membrane is also investigated. There is next considered the case of torsional waves in the rod giving rise to radial torsional waves in the attached membranes which now may be treated either as flexible or rigid diaphragms. When the latter are rigidly clamped at their outer edges, the structure is found to be a high‐pass torsional wave filter. When the diaphragms are free at the outer edges, a low‐pass filter results. The transmission characteristics are given for each case along with numerical illustrations.

A Compound Horn Loudspeaker

Harry F. Olson and Frank Massa

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 48-52 (1936); (5 pages)

Online Publication Date: 15 Jun 2005

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A new type of loudspeaker is described in which a single mechanism is coupled to two horns: a straight axis high frequency horn and a folded low frequency horn. A theoretical analysis of the combined system is given and experimental data are shown which indicate smooth uniform response from 50 to 9000 cycles, and an efficiency of the order of 50 percent over a large portion of this range.

The Theory of Sound Absorption of Porous Materials, Flexible and Nonflexible

Michael Rettinger

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 53-59 (1936); (7 pages)

Online Publication Date: 15 Jun 2005

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Mechanical Vibrations at Radiofrequencies

R. C. Colwell and L. R. Hill

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 60-61 (1936); (2 pages)

Online Publication Date: 15 Jun 2005

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Musical Instruments and Acoustical Science

William Braid White

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 62-63 (1936); (2 pages)

Online Publication Date: 15 Jun 2005

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Fifteenth Meeting of the Acoustical Society of America (A)

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 65-69 (1936); (5 pages)

Online Publication Date: 15 Jun 2005

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Studies of the Vibro‐Tactile Senses as Means for Determining Direction (A)

Robert H. Gault

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 65-65 (1936); (1 page)

Online Publication Date: 15 Jun 2005

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Earlier investigations in this field have left the factors of intensity, rate of transmission (and consequently time of stimulation) and phase without adequate control. In this investigation, as far as it has proceeded, we have attempted to supply this deficiency.
In the experimenter's room is a speaker that may be moved right or left upon the arc of a circle. Before it, in fixed positions, are two microphones. These microphones communicate with two vibrators, respectively, in the distant observer's room. The observer is seated with the index finger of the right hand upon one vibrator and that of the left hand upon the other. The situation is so arranged that he cannot hear the action of the vibrators. Before him, and covering the vibrators, is a sheet of cardboard on which the arc of a semicircle is described marked to designate degrees.
As the speaker, in action, is moved sufficiently to the right or left, thus varying its distance from the microphones, respectively, the intensity, time and phase of the stimulus upon the observer's fingers, respectively, are altered as in a corresponding situation in the sphere of audition. The observer “feels as if” a vibrating body before him were moving between right and left. On the semi‐circumference before him he designates the degree of the apparent movement.
When, now, the speaker is kept in a constant middle position with reference to the microphones and when attenuators are introduced to control intensity in the vibrators, respectively, the time element is kept constant but the observer continues to experience the illusion of movement referred to. The degree of apparent movement corresponds to that that obtains in the auditory sphere in similar situations.
We have yet to complete the experiment by holding intensity constant while other factors are independently varied.
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Articulation Testing by Bone Conduction (A)

N. A. Watson

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 65-65 (1936); (1 page)

Online Publication Date: 15 Jun 2005

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The paper describes briefly the apparatus used for transmitting the recorded articulation lists to the bone‐conduction vibrator, and the construction of the induction type electrodynamic vibrator itself. Results of articulation tests on normal‐hearing persons are given which indicate that, with high quality apparatus and sufficient power, articulations can be obtained by bone conduction as high as those by air conduction. 100 percent often being attained. The variation of percent syllable articulation with increasing level is given for bone conduction for open ear canals and for partially blocked canals. The effects of the following factors on percent syllable articulation are also discussed: (1) Variation of total force and pressure of the vibrator against the observer's head; (2) frequency and nonlinear distortion in the amplifier system; (3) use of multiple vibrators; and (4) clenching of teeth and other variations of the condition of the observer's head.
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The Present Status of the Mechanics of Sound Conduction in Its Relation to the Possible Correction of Conduction Deafness (A)

A. G. Pohlman

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 65-66 (1936); (2 pages)

Online Publication Date: 15 Jun 2005

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E. H. Weber in 1851 interpreted the middle ear apparatus as an impedance matching transformer which balanced the resistance differences between the medium of conduction (air) and the medium of reception (liquid). The interpretation implied that the apparatus must be effective for all audiofrequency levels. It was not accepted by otologists because it was known that in conduction deafness, greater functional disability is noted for the low than for the high frequencies. Recent developments support the Weber interpretation and indicate that this low pitch disability is not dependent on frequency limitations due to the pathology of the middle ear. Evidence will be submitted to show that where the sound conduction apparatus is nonfunctional the drum membrane damps the direct conduction through the air of the middle ear. A case will be reported on the replacement of the lost drum membrane and ossicles by a prosthesis patterned after the middle ear apparatus of the bird. The possibility of creating a soft spot in the otic capsule in cases where the stapes is “frozen” to the head so that a transformer prosthesis may be applied will be considered. The accepted idea of a mass shuttling in the labyrinth liquid as the mechanical factor essential to audition is opposed.
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The Influence of Intensity on the Pitch of Violin and 'Cello Tones (A)

Milton Cowan and Don Lewis

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 66-66 (1936); (1 page)

Online Publication Date: 15 Jun 2005

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Three independent investigators (Zurmühl, Stevens and Fletcher) have recently shown that significant changes in the pitch of certain pure tones accompany changes in their intensity, the amount of change depending upon both frequency and intensity. The question naturally arises as to whether the pitch of complex musical tones is similarly related to intensity. The present paper is the report of an investigation which was undertaken to answer this question insofar as it relates to violin and 'cello tones. The results are not entirely unequivocal, but they tend to show that intensity has no measurable effect on the pitch of the tones studied. Intensity may affect the pitch of these tones but, if it does, the pitch‐intensity relationship here is basically different from that operative in the case of pure tones; and this is unlikely.
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The Legal Problems of Noise (A)

E. E. Free and D. J. Hahn

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 66-66 (1936); (1 page)

Online Publication Date: 15 Jun 2005

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Records obtained by standard noise meters are beginning to be accepted by American courts as legal evidence in nuisance cases, but the legal definition of what constitutes a noise nuisance is not clear. Existing and possible principles and some leading cases will be discussed. Acoustical engineers might usefully work out and suggest certain physical or physiological principles which should underlie new legal definitions in line with modern methods of noise measurement.
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Automotive Quieting (A)

R. F. Norris

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 66-66 (1936); (1 page)

Online Publication Date: 15 Jun 2005

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Intake roar, exhaust noise and body resonance are discussed. Methods by which these noises are attacked are explained and data showing their relative importance are given.
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Application of Elastic Suspensions to High Speed Newspaper Presses (A)

Stanley D. Livingston

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 66-67 (1936); (2 pages)

Online Publication Date: 15 Jun 2005

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The effectiveness of various types of elastic suspensions when applied to complex mechanisms has been determined from an analysis of the test data which were obtained from several multi‐unit newspaper press installations. Materials used as isolation mediums were natural cork, rubber pads and steel springs. The weight of the various installations ranged from four hundred and fifty tons to nine hundred and fifty tons. A semirigid assembly of press units now being erected will have a total sprung weight of approximately twelve hundred tons.
The vital question in the case of the original installation, which was made solely for the purpose of reducing the nuisance effect of the vibration transmitted to the building structure, pertained to the degree of elasticity permissible without materially affecting the production efficiency of the presses. It has been found that the transmission of vibration can be reduced to a minimum, and, if the suspension is properly applied, the production efficiency can be materially increased. Accordingly, some suspensions are now being installed solely for economical reasons.
The writer offers for discussion the subject of the transmission of vibration by means of “carrier frequency” and questions whether this phenomenon has been given the attention it merits.
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Developments in Aircraft Sound Control (A)

H. Bruderlin and E. Wheaton

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 67-67 (1936); (1 page)

Online Publication Date: 15 Jun 2005

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This paper describes present requirements for sound control in larger airplanes from the viewpoints of the operator, the passenger, and the manufacturer. It presents a new method of approach to the problem of satisfying these requirements, showing measures being taken toward their solution on a new aircraft project, and giving anticipated results.
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A Method of Eliminating Cavity Resonance, Extending Low‐Frequency Response and Increasing Acoustic Damping in Cabinet Type Loudspeakers (A)

Benj. Olney

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 67-67 (1936); (1 page)

Online Publication Date: 15 Jun 2005

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When a direct‐radiator loudspeaker is mounted in a cabinet, as in the conventional radio receiver, response irregularities are introduced because of resonances in the space behind the loudspeaker. With a cabinet and speaker diaphragm of ordinary size, the acoustic load at low frequencies is highly reactive, the radiation efficiency is very low and diaphragm amplitudes become excessive.
In the method described, the rear of the loudspeaker diaphragm is tightly coupled to one end of a folded conduit lined with sound‐absorbing material and terminating in an opening in the bottom of the cabinet. This arrangement is called an acoustical labyrinth. By suitable tuning of the conduit, an extension downward of the reproduced frequency range is secured. The acoustic impedance of the conduit is shown by measurement to offer a diaphragm load having desirable characteristics, it being predominantly resistive over virtually the entire measured low frequency range (40–350 cycles). Measurements of the acoustic impedance on the front of a diaphragm in a moderate sized baffle and of the impedance facing the back of a diaphragm in a conventional radio cabinet are also reported. The improvement in the frequency characteristic of a cabinet type loudspeaker afforded by the use of the acoustical labyrinth is shown by response curves.
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Loudspeakers for High‐Fidelity Large Scale Reproduction of Sound (A)

Frank Massa

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 67-67 (1936); (1 page)

Online Publication Date: 15 Jun 2005

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The extension of both frequency and volume range in large scale sound reproduction has imposed severe limitations on the performance characteristics of loudspeakers employed in these applications. This paper discusses some of the problems that arise under such conditions and what means have been taken for their solution. The limitations of single speakers to cover the entire frequency range are mentioned and the advantages of multi‐speaker systems are pointed out.
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Control of Temperature Variation in the Frequency of Tuning Forks (with demonstrations) (A)

B. E. Eisenhour

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 67-67 (1936); (1 page)

Online Publication Date: 15 Jun 2005

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The increasing use of tuning forks not only as frequency standards but as controlling devices for equipment requiring perfect synchronization calls either for very accurate temperature control with the ordinary steel fork, or for the development of forks in which the variation of frequency with temperature is negligibly small.
Two methods have been employed to achieve this end—either the development of metal alloys having very small frequency‐temperature coefficients, or the fabrication of compensated forks from two materials having coefficients of opposite sign. While alloy steels, such as Invar and Elinvar, can be produced having coefficients of the order of one‐twentieth that of ordinary steel, yet very considerable variations in coefficients are found in individual samples of these alloys even when cut from the same piece of stock.
The combination of two alloys having positive and negative temperature coefficients has proven a more practical means of producing forks of uniform qualities and with frequencies independent of temperature. Demonstrations of the thermal properties of forks of this type will be made.
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Variation of Sound Absorption with Area (A)

V. L. Chrisler

J. Acoust. Soc. Am. Volume 8, Issue 1, pp. 67-67 (1936); (1 page)

Online Publication Date: 15 Jun 2005

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Sound absorption measurements have been made in the reverberation chamber by an intensity method on areas of 72 square feet and areas of 4 square feet. The apparent coefficient is larger for the small areas and agrees within the error of measurement with results which were obtained by the reverberation method.
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