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Journal of the Acoustical Society of America

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Jan 1967

Volume 41, Issue 1, pp. 1-223

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Interaction of the Auditory and Visual Sensory Modalities

A. E. Brown and H. K. Hopkins

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 1-6 (1967); (6 pages)

Online Publication Date: 21 Jul 2005

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The general observation that dual sensory input enhances signal detectability is of considerable interest from the information‐processing standpoint. Previous experiments on the effects of intersensory interaction have been concerned primarily with an observer's performance on a vigilance task. These studies have not produced results that are sufficiently precise to define the extent and manner of sensory interaction. This study is concerned with obtaining precise measurements of interaction occurring between auditory and visual sensory‐information‐processing networks. Separate auditory and visual threshold functions are determined and analyzed in terms of signal‐detection theory. A bisensory threshold function is also determined, using equated stimuli levels derived from the individual sensory functions. The results of the bisensory test are compared to a theoretically derived curve based on the hypothesis of probabilistic adding and are found to have good correspondence.

Critical Band in Binaural Detection

B. E. Mulligan, M. J. Mulligan, and J. F. Stonecypher

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 7-12 (1967); (6 pages)

Online Publication Date: 21 Jul 2005

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In order to account for binaural improvements in detection on the basis of interaural phase shifts, or time deviations, it is necessary to assume that the “critical band” is a sinusoidlike process and that corresponding processes from the two ears interact. Support for this assumption is reported for the binaural conditions N0Sπ, NπS0, N0S0, N0Sm, and NπSm. It was found that neither interaural level nor bandwidth differences matter so long as the levels within the critical bands at the two ears are unaffected. Detection at one ear is affected only by a narrow band of frequencies at the opposite ear, thus confirming the assumption of a band‐limited binaural interaction. Experiments were carried out with three different maskers: a narrow‐band noise, a medium‐band noise, and a medium‐band noise with a gap in it. The narrow‐band masker was as effective as the medium‐band masker. The noise with a gap in it, however, produced a minimal release from masking when added at the nonsignal ear. These findings are discussed within the context of those of earlier investigations.

Integration of the Energy in Repeated Tone Pulses by Man and the Goldfish

George C. Offutt

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 13-19 (1967); (7 pages)

Online Publication Date: 21 Jul 2005

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A basic difference is shown to exist between the hearing of man and that of the goldfish. The goldfish possesses a direct relationship between the sound energy (percent of time that the tone is on) and its threshold, which is lowest with continuous tones. In humans, however, the threshold is dependent upon the duration of each tone pulse. With long‐tone pulses, the human threshold is lower than with continuous tones. It is hypothesized that this difference is due to a lack of adaptation in the goldfish auditory nerves, whereas the human has increased nervous activity at the beginning and end of each tone pulse. Thus, the level of sensation in the human appears to depend on the amount of nervous activity produced in the receptor by a stimulus pulse. These findings show that the fish are relatively better adapted to hearing the kinds of sounds found in their natural environment than is the human observer. Some ideas are presented as to how the determination of tone‐pulse thresholds could aid in certain clinical investigations.

Accumulation Theory of Binaural‐Masked Thresholds

K. D. Schenkel

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 20-31 (1967); (12 pages)

Online Publication Date: 21 Jul 2005

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Two models describing binaural‐masked thresholds (the delay‐line model and the EC model) are checked by extended experiments. They prove only a limited validity. Therefore, a new model, the accumulation model, is proposed, one that does not use any delay at all and that is, therefore, able to process interaural differences on a more general basis. It is in full agreement with former calculation schemes for monaural‐masked thresholds. This model explains all effects in binaural masked thresholds known so far. Binaural‐masked thresholds computed according to this model are in good agreement with experimental data.

External Surface‐Absorption Cross Section of a Pipe Organ

A. H. Benade

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 32-38 (1967); (7 pages)

Online Publication Date: 21 Jul 2005

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The total sound absorption due to a rank of organ pipes arises chiefly from internal resonance losses and also from energy dissipation taking place at the external surfaces of the pipes. The first contribution has been discussed elsewhere [A. H. Benade, J. Acoust. Soc. Am. 38, 780–789 (1965)], and the second is reported here. Scattering of a plane wave incident obliquely on a long circular cylinder is calculated, and the results are used to find the energy absorbed via viscosity and also via the short‐circuiting of the wave's temperature fluctuations produced by an isothermal boundary. It is shown that an absorption coefficient can be defined for the pipe surface that is approximately independent of the radius/wavelength ratio. The corresponding coefficient for viscous and thermal losses at a plane surface is also calculated. The result are mathcyl  =  2.3⋅10−5(ω)½ and mathPLANE  =  6.8⋅10−5(ω)½. The latter result agrees with a calculation by Walther [J. Acoust. Soc. Am. 33, 127–136 (1961)]. Computation of the absorption by a rank of pipes is simplified by using the scaling principles followed by organ builders. It is shown that the external absorption is negligible below 500 Hz, and is only about 0.06 m2 at 2000 Hz for a 73‐pipe rank centered at middle C.

Synthesis of Wind‐Instrument Tones

William Strong and Melville Clark

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 39-52 (1967); (14 pages) | Cited 3 times

Online Publication Date: 21 Jul 2005

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Clarinet, oboe, bassoon, tuba, flute, trumpet, trombone, French horn, and English horn tones have been synthesized with partials controlled by one spectral envelope (fixed for each instrument regardless of note frequency) and three temporal envelopes. Musically literate auditors identified natural tones with 85% accuracy and our synthesized tones with 66% accuracy; a number of the confusions were intrafamily. With intrafamily confusions tolerated in the scoring, the auditors identified natural tones with 94% accuracy and our synthetic ones with 77% accuracy.

Analysis of Pure‐Tone Audiometric Responses in Relation to Speech Development in the Profoundly Deaf

G. W. G. Montgomery

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 53-59 (1967); (7 pages)

Online Publication Date: 21 Jul 2005

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The results of binaural audiometric tests of 83 profoundly deaf children were compared with their scores on a standardized speech test (the Phoneme Count), the American Medical Association (1947) audiogram‐average assessment of percentage hearing loss for speech, and a qualitative diagnosis of speech defect. A contingency table of responses at 10‐dB intervals against seven frequencies in both ears was compiled, and nonparametric analyses were undertaken to ascertain “speech frequencies” for this population. Mean standardized speech test scores per intensity interval appeared, by inspection, to be associated positively with residual hearing at all frequencies from 125 to 8000 cps in both ears, but a formal chi‐square test of the association of speech scores and a response/no‐response measure of each frequency from 125 to 8000 cps established significant relationships 4000 and 250 cps for the worse ear and at 2000, 250, 125, 1000, and 4000 cps for the better ear. The importance of lower frequencies as useful indicators of potential speech development in the profoundly deaf was noted, and the possibility of predicting eventual speech performance from the pure‐tone audiogram was suggested. A lowering of frequency limits and a raising of the level of decibels above normal threshold was advocated for any audiogram‐average method that sought to summarize hearing loss for speech for the profoundly deaf.

Time Adjustment in Speech Synthesis

Robert J. Scott

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 60-65 (1967); (6 pages)

Online Publication Date: 21 Jul 2005

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Fairbanks' speech time‐adjusting device has been simulated, using a hybrid computer. This device discards or repeats recorded speech segments to compress or expand the time dimension. A dichotic method for time compression of speech was investigated in which odd‐numbered time segments were presented to one ear and even‐numbered segments to the other ear. A preference test suggested that speech compressed with the dichotic method may be more intelligible than speech compressed with Fairbanks' method. Potential applications for time‐adjusted speech and possibilities for further research are suggested.

Phonemic Analysis of Consonants in Helium Speech

Russell L. Sergeant

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 66-69 (1967); (4 pages)

Online Publication Date: 21 Jul 2005

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A phonemic‐confusion matrix for speech in a helium atmosphere was constructed for use in predicting intelligibilities of specially constructed vocabularies for such environments. There is a marked similarity between helium speech and speech in air when intelligibility according to linguistic classification is observed. However, unaccountable differences do exist between the two breathing media for ranked intelligibilities of specific consonants.

Technique for Correcting Helium Speech Distortion

W. R. Stover

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 70-74 (1967); (5 pages) | Cited 1 time

Online Publication Date: 21 Jul 2005

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Some qualitative data on the nature of the speech distortion caused by respiration of a helium‐oxygen atmosphere are presented. Previous corrective‐processing techniques are discussed, and an advanced technique that overcomes their disadvantages described. The experimental system is based upon time‐domain speech‐processing methods and is capable of retaining the natural pitch rate of the speaker's voice while correcting the formant shifts caused by the helium‐rich atmosphere. This system uses digital‐processing methods and is capable of operating on continuous speech in on‐line applications. It promises a practical solution to the problem of providing normal voice communication in a helium environment.

Measurement of the Piezoelectric Constant of Quartz at Gigacycle Frequencies

Paul H. Carr

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 75-83 (1967); (9 pages) | Cited 4 times

Online Publication Date: 21 Jul 2005

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The piezoelectric constants of selected samples of X‐, AC‐, and BC‐cut quartz have been measured in the range 1–5 Gc/sec and are found equal to the static and megacycle values (i.e., d11  =  2.3 × 1012 and d14  =  −0.67 × 1012 C/N) within an experimental uncertainty of 10%. This establishes that the piezoelectric constants of quartz are frequency‐independent up to gigacycle frequencies. Gigacycle acoustic waves were generated at the end surface of a quartz rod places in the electric field of a re‐entrant cavity. The piezoelectric constant was determined from a measurement of the cavity insertion loss and the cavity filling factor. A perturbation method has been developed for directly measuring the latter, which has previously been assumed to be unity. The method involves the use of perturbation theory to compute the filling factor, or equivalently, the electric field generating the acoustic waves, from a measurement of the decrease in the cavity resonant frequency when the rod is moved a small distance into the cavity. The piezoelectric constant of some quartz samples is less than that of the selected samples, and this decrease is attributed to defects in the optically polished end surface where the phonons are generated.

Ultrasonic Orientation Determination of Single Crystals

Robert E. Green, Jr. and Edmund G. Henneke, II

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 84-90 (1967); (7 pages) | Cited 2 times

Online Publication Date: 21 Jul 2005

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A general method for determining crystallographic orientation by measurement of velocities of propagation of ultrasonic waves is given. The method supplements optical and x‐ray techniques and is primarily designed for orienting crystals to be used in ultrasonic pulse experiments. Aluminum and zinc single crystals are used as specific examples of the method. The required accuracy for such measurements is discussed.

Exact Simplification of Time‐Dependent Ultrasonic‐Standing‐Wave Light‐Diffraction Equations

L. E. Hargrove

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 91-92 (1967); (2 pages)

Online Publication Date: 21 Jul 2005

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A considerably simpler mathematical form of the equations for the intensity of light diffracted by ultrasonic standing waves with arbitrary standing‐wave ratio is derived from an existing solution. The simplification—which results from mathematical identity, not from approximations—reduces a double summation of Bessel function products to the square of a single Bessel function.

Effect of Diffusion on Ultrasonic Attenuation in Mixtures of the Rare Gases

Andre K. Law, N. Koronaios, and R. B. Lindsay

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 93-99 (1967); (7 pages) | Cited 3 times

Online Publication Date: 21 Jul 2005

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The attenuation of 70‐kHz sound in mixtures of helium and argon and of helium and krypton has been measured over a temperature range from 23° to 140°C and a pressure range from about 20 to 200 mm Hg. Kohler's theory of absorption due to diffusion in a mixture of two monatomic gases is found to account successfully for the measured excess absorption over that due to viscosity and thermal conductivity. Total absorption is found to increase slightly with temperature, a result that may be ascribed to the nonrigidity of the gas molecules. Generally good agreement is found with the previous room‐temperature measurements of Petralia, Holmes and Tempest, and Stavseth.

Vibrational Relaxation in Carbon Dioxide/Helium Mixtures

J. W. L. Lewis and F. D. Shields

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 100-102 (1967); (3 pages) | Cited 5 times

Online Publication Date: 21 Jul 2005

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Sound‐absorption and ‐dispersion measurements have been made using the tube method on gas mixtures of carbon dioxide and helium over the temperature range 25° to 191°C. The data obtained indicate a single relaxation‐time process, and the maximum absorption per wavelength agreed, within experimental error, with the theoretical values. The reciprocal of the relaxation time of the mixture was found to be a linear function of the mole fraction of helium. The number of CO2/He collisions necessary to de‐excite the deformation mode vibration was found to decrease linearly when plotted versus T−⅓ from 3222 at 25°C to 1376 at 191°C.

Acoustic Velocity with Relation to Chemical Constitution in Alcohols

Graham W. Marks

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 103-117 (1967); (15 pages) | Cited 1 time

Online Publication Date: 21 Jul 2005

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The results of this investigation extend and confirm conclusions given in the literature deduced from sound velocity and auxiliary data concerning alcohols. Acoustic velocities at 500 kcps were measured in a large number of alcohols and in three series of alcoholic binary solutions with a precision ultrasonic interferometer within the temperature range of 0°–80°C. Viscosities were determined at 25°C and densities within the range 14°–37°C. At fixed temperature, increase in sound velocity with increase in number of carbon atoms in primary alcohols follows a simple exponential law. The square root of the viscosity varies inversely as the molecular sound velocity. Secondary alcohols have lower sound velocities than the corresponding primary isomers because of lower densities. The increment in van der Waals' b per CH2 group is about 20 cm3 per mol. This holds true for all the homologous series studied. Fluorinated alcohols have much lower sound velocities than the alcohols from which they were derived. Rao′s constant (molecular sound velocity) drifts somewhat with temperature, which is to be expected for associated liquids. The three series of binary solutions studied were n‐propanol and isopropanol, n‐propanol and n‐octadecanol, and aqueous solutions of a propane diol derivative. Apparent molal adiabatic compressibilities for the component taken to be the solute vary as the square root of the molality at fixed temperatures.

Two‐Dimensional Anisotropic Acoustic Diffraction

Edward Gates

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 118-125 (1967); (8 pages) | Cited 1 time

Online Publication Date: 21 Jul 2005

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A scalar two‐dimensional acoustic Green's function that is valid for particular orientations of several crystal classes is derived. The function is used to find expressions for aperture diffraction, array radiation, and radiation from a point source above a boundary. These results, if compared to similar calculations for isotropic media, show anisotropic variations that are dependent on the group velocity.

Omnidirectional Scattering of Acoustic Waves by Rough, Imperfectly Reflecting Surfaces

B. E. Parkins

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 126-134 (1967); (9 pages)

Online Publication Date: 21 Jul 2005

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The omnidirectional scattering of acoustic waves by a rough, imperfectly reflecting surface is described using the method of physical optics. The expression for the far‐zone intensity is derived and then specialized to the case of surfaces that are sufficiently rough to neglect the specularly reflected power. For such surfaces, the average differential scattering cross section σ0 is calculated and compared with the results of bistatic measurements made under conditions that satisfy the assumptions of the theory.

Measurement of the Attenuation Constant in a Tube Having Uniform Cross Section

Joseph W. Rogers

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 135-137 (1967); (3 pages)

Online Publication Date: 21 Jul 2005

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The theory and the experimental technique for measuring the attenuation constant in a tube are given. No moving parts are required, nor is there any need to calibrate the couplings of any microphones. The attenuation constant is found to be 2π⋅Δf/c, in which Δf is the difference in frequency to be measured and c is the speed of sound in the tube.

Shadowing of Randomly Rough Surfaces

R. J. Wagner

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 138-147 (1967); (10 pages) | Cited 5 times

Online Publication Date: 21 Jul 2005

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The first‐order probability densities of height and slope on the portions of a rough surface illuminated jointly by rays in two arbitrary directions have been evaluated for a surface generated by a stationary normal random process. The dependence of the statistical properties of the apparent surface on the angles of incidence and observation is illustrated. For the case of backscatter, a simple calculation of the “shadowing functions,” valid at very small grazing angles, and a more detailed approximation, valid at the larger angles, are shown to be in excellent agreement with the computer‐simulation results of Brockelman and Hagfors.

Normalized Numerical Solutions for Rayleigh's Frequency Equation

D. S. Potter and C. D. Leedham

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 148-153 (1967); (6 pages) | Cited 2 times

Online Publication Date: 21 Jul 2005

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In this paper, limiting forms of a transcedental‐frequency equation, attributed originally to Lord Rayleigh, are derived. The limiting forms are examined and their roots are used to find the exact normalized roots the original equation in the complex plane. A comprehensive collection of roots, considerably more extensive than that currently available, is tabulated for a range of normalized frequency.

Volume‐Scattering Measurements at 12 kc/sec in the Western Pacific

W. E. Batzler and R. J. Vent

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 154-157 (1967); (4 pages)

Online Publication Date: 21 Jul 2005

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Acoustic volume scattering data at 12 kc/sec from 14 deep‐water areas lying in the region 5°–45°N and 115°–175°E in the Western Pacific are presented. Results are shown graphically as volume‐scattering coefficient (and scattering strength) vs depth. Volume‐scattering‐coefficient values (expressed in decibel form) range from about −50 to −95 dB. There is considerable variation from area to area; the more southerly areas have the lower scattering coefficients, and scattering layers observed there are less well defined. Most intense scattering occurred in an area northeast of Honshu, Japan, where layers 500 ft thick with a peak scattering coefficient near −50 dB were observed. Scattering levels show a rough dependence on latitude and a somewhat stronger correlation with estimates of organic productivity. Volume‐scattering coefficients observed off Southern California are usually higher by 5–15 dB than those in the Western Pacific areas.

Free‐Flooding Unidirectional Resonators for Deep‐Ocean Transducers

R. E. Horita

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 158-166 (1967); (9 pages) | Cited 1 time

Online Publication Date: 21 Jul 2005

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An array of compound piezoceramic metal resonators can be made to radiate sound preferentially in one direction without auxiliary acoustic baffles if suitable geometries and material combinations are selected. This has the advantage that depth independence and high power‐to‐weight ratio are obtained. Expressions have been derived for the farfield front‐to‐back pressure ratio, the electromechanical coupling coefficient, and the mechanical Q for resonators with flared conical metal heads, cylindrical piezoceramic shanks, and tapered conical metal tails. The results of the analysis and supporting experimental work show that it is feasible to design practical, high‐performance sound projectors for deep ocean operation attaining unidirectionality without the use of baffles.

Refracted/Reflected Ray Transmissions in a Divergent Channel

Melvin J. Jacobson and John G. Clark

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 167-176 (1967); (10 pages)

Online Publication Date: 21 Jul 2005

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Refracted/bottom reflected ray transmissions in a divergent channel are studied when the sound velocity decreases linearly with depth. Ray geometry is examined in detail and, for a fixed source and receiving point, the number of arrivals, travel time, and spreading loss are found. For the source and receiving point on the channel bottom, bounds on the acceptable initial inclination angle, travel time, number of bottom reflections, and spreading loss are determined. Further, spreading losses in divergent and horizontal channels are compared. Spreading loss is also examined at all points along a ray emanating from a bottom source. In an example, bottom loss and bottom phase shift are superimposed upon spreading loss and travel‐time phase shift, respectively, and the concept of bottom‐induced interference is discussed.

Calculation of an Average Backscattering Coefficient of a Scattering Layer in a Frequency Band

A. Mohammed

J. Acoust. Soc. Am. Volume 41, Issue 1, pp. 177-181 (1967); (5 pages)

Online Publication Date: 21 Jul 2005

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The concept of a backscattering coefficient of a layer of isotropic scatterers averaged over a frequency band determined by the spectral characteristics of the transmitted signal and of the receiving equipment is introduced. The coefficient is evaluated for special cases of signal and receiver spectral shapes; numerical results of practical utility are included. The analysis neglects interaction effects among the scatterers and time variations of the medium.
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