• Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Journal of the Acoustical Society of America

SECTION LISTING

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

Apr 1964

Volume 36, Issue 4, pp. 639-790

Page 1 of 2 Pages Next Page | Jump to Page

New Display Format and a Flexible‐Time Integrator for Spectral‐Analysis Instrumentation

David E. Wood

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 639-643 (1964); (5 pages)

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
Continuing development has increased the capabilities of the spectral‐analysis instrumentation reported earlier [D. E. Wood and T. L. Hewitt, J. Acoust. Soc. Am. 35, 1274–1278 (1963)]. This analyzer operates in real time by very rapid scanning of the outputs of a bank of bandpass filters. A unique process of true interpolation generates continuous spectral cross sections that preserve accurate frequency relations of signal components. The cross sections are recorded on strip film by photographing their display on a CR tube. Spectrographic‐picture formats previously described include complete cross‐section records and spectrograms showing amplitude by intensity‐modulation. A new display technique clarifies frequency patterns by marking just at the amplitude maxima or “peaks” in spectral cross sections. The simplified picture of the spectral “hilltops” pinpoints the frequencies and frequency modulations of features such as speech formants. This binary type of picture requires no grey scale and improves the resolution of small features. The “peak” display may be combined with other formats by means of a selector‐combiner device. A novel analog integrator now provides flexible time‐averaging by adding spectral cross sections in numbers variable from 2 to over 1000. The periods of averaging can be overlapped and the integrator could be equipped to provide simultaneous multiple outputs representing different averaging periods. The analyzer system is organized to take full advantage of the various kinds of flexibility with a minimum of operational steps. The combination of simple control, real‐time operation, and strip‐film recording provide the capabilities for large‐scale investigations, while flexibility of analysis and display increase the information to be seen in the spectrographic pictures.

Ultrasonic‐Wave Propagation in Pure Silicon and Germanium

Warren P. Mason and T. B. Bateman

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 644-652 (1964); (9 pages) | Cited 23 times

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
Ultrasonic attenuation and velocity measurements have been made in pure germanium and silicon (doping <1014 impurity atoms per cc) and in doped n‐type germanium and p‐type silicon. The attenuation in pure materials shows a continuous decrease as the temperature is decreased and a very low attenuation below 20°K. These results indicate that the energy losses are accounted for entirely by phonon‐phonon interactions. A calculation has been made of these losses, using a model based on the Akheiser effect and incorporating the recently measured third‐order elastic moduli of silicon and germanium. For both materials, the calculated values predict correctly the large difference between longitudinal and shear waves and agree quantitatively within 50% with the measured values over the whole temperature range.

Propagation of Axisymmetric Waves in a Circular Semiinfinite Elastic Rod

R. K. Kaul and J. J. McCoy

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 653-660 (1964); (8 pages) | Cited 2 times

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
The Mindlin‐McNiven equations for axially symmetric waves are used to determine the radial strains in a circular, semiinfinite, isotropic, elastic rod for both pure and mixed end conditions when a constant pressure is suddenly applied to its end. Using double‐integral transforms, the solution is obtained in terms of three Fourier integrals, each one representing one mode of propagation. These integrals are too complex to be evaluated exactly and, therefore, an asymptotic solution, valid for large distance of travel, is obtained for the head of the pulse by using the method of steepest descent. The results predict the existence of edge resonance and further demonstrate its influence on the strain field.

Collective Sound Mode in a Two‐Component Fluid

Richard L. Liboff

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 661-665 (1964); (5 pages) | Cited 3 times

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
Starting with two Boltzmann‐like equations, a kinetic theory is made of the long‐wavelength disturbances that propagate in a two‐component neutral fluid. A transition is observed from separate adiabatic sound speeds for each gas in the case of weak coupling to the single adiabatic sound speed of the gas mixture plus strongly damped relative motion in the opposite extreme of strong coupling between the gases.

Axisymmetric Vibrations of Thin Elastic Shells

C. N. DeSilva and G. E. Tersteeg

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 666-672 (1964); (7 pages) | Cited 1 time

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
The first part of this paper treats the axisymmetric transverse vibrations of membrane shells. The stress differential equations of motion with longitudinal inertia neglected are solved for a class of shells that includes the ogive, cone, cylinder, and sphere. The emphasis is placed on predicting the lowest natural frequency of vibration for shells with a free boundary. These frequencies are compared with the previously known results of the bending solutions for the shallow spherical‐shell segment and for the hemispherical shell. In the second part, attention is turned to the shell whose mode of deformation is primarily flexural by applying hypotheses associated with edge effects. The deformation is specified by a pair of differential equations that are solved for a class of shells of revolution. The frequency equation is obtained and particularized to specific geometries.

Dynamic Absorbers Applied to a Bar That Has Solid Damping

V. H. Neubert

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 673-680 (1964); (8 pages) | Cited 1 time

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
The theoretical steady‐state response of an axially excited bar having solid damping is determined. The effect of adding one or two dynamic absorbers is considered, as well as the effect of adding concentrated mass only. Tuning of the absorbers and optimization of damping are discussed.

Wave Propagation in a Medium with Random, Spheroidal Inhomogeneities

G. C. Knollman

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 681-688 (1964); (8 pages) | Cited 2 times

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
An acoustic or electromagnetic wave propagating in a material medium experiences fluctuations in amplitude and phase that can be attributed in part to scattering from inhomogeneities due to variations in the refractive index of the transmission medium. Since such “patches of inhomogeneity” are often regarded as lenticular in shape, it is the purpose of this paper to extend, for both plane and spherical sound waves, contemporary wave‐fluctuation theory (based on a Gaussian correlation function for refractive index) to include the circumstance of spheroidal inhomogeneities. Mean‐square amplitude and phase fluctuations are considered for acoustic waves propagating in a statistically isotropic medium in which random deviations of the refractive index are small. Large‐scale inhomogeneities of arbitrary spheroidal shape are treated, and the influence of transmitter‐to‐receiver range, acoustic wavelength, and “patch” dimensions on variations in wave amplitude and phase is derived for this general case. Particular attention is given the high‐frequency ray limit (Bergmann region) and the low‐frequency (Fraunhofer diffraction) region. The significant effects on wave fluctuations of both spherical and nonspherical inhomogeneities are compared for plane and spherical acoustic waves.

Acoustic Rays in an Ocean with Heat Source or Thermal‐Mixing Zone

Hans J. Lugt and Peter Uginčius

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 689-694 (1964); (6 pages)

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
The eikonal equation of ray acoustics is discussed for the general case, with the index of refraction a function of the three space coordinates. Two examples illustrating the influences of a two‐dimensional heat source and a thermal‐mixing zone on the acoustic‐ray paths are presented. Numerical results show that, for long‐range acoustical ray tracing, inhomogeneities of the ocean in the horizontal plane can cause refraction effects, which are not negligible in comparison with effects due to vertical inhomogeneities. Rays, which travel in the vicinity of a heat source, can be refracted as much as 6°. Thermal‐mixing zones can increase the range of shadow zones near the ocean surface up to 50%. Even new shadow zones can be formed.

Sensitivity of Liquid‐Filled, End‐Capped, Cylindrical, Ceramic Hydrophones

G. W. McMahon

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 695-696 (1964); (2 pages) | Cited 1 time

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
A theoretical expression is developed for the sensitivity of liquid‐filled, cylindrical, ceramic hydrophones having rigid and semirigid end caps. The theory gives good agreement with experimental measurements on a lead zirconate‐titanate hydrophone with two end‐cap conditions and three different enclosed fluids.

Interaction between Sound and Flow in Acoustic Cavities: Mass, Momentum, and Energy Considerations

R. H. Cantrell and R. W. Hart

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 697-706 (1964); (10 pages) | Cited 7 times

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
This paper investigates requirements for neutral acoustic stability in cavities with a transpiring wall where there is a mean flow in the absence of acoustic disturbances. The growth rates of the acoustic fields are also considered. The method of calculation utilizes time averages of the mass, momentum, and energy‐conservation equations to second order in the acoustic‐field quantities. It is found that growth rate and neutral stability may be expressed in terms of only first‐order quantities. The results are shown to be in agreement with those calculated from first‐order admittance considerations, but differ, in general, from those of Dyer, who uses a method of calculation similar to the present paper. The resolution of this conflict is discussed. The effect of mean flow is often of considerable importance, and the extent to which flow tends to excite or damp the acoustic field is related to mode configuration and flow‐field geometry. Application to the problem of determining the acoustic response of burning rocket propellants is discussed.

Effect of Boundary Flexibility on the Response of a String to Convected Random Loading

Pritchard H. White

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 707-716 (1964); (10 pages)

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
The mean‐square displacement of a uniform, stretched string, restrained against lateral movement at the boundaries by springs, to a convected, random‐loading field has been investigated. A modal‐analysis technique based on Powell's method has been used, all crosscoupling terms being retained. The response is strongly affected by two parameters: the ratio of convection velocity to the wave velocity of the string (u/a) and the ratio of wavenumber of the excitation to wavenumber of the eigenfunction of the string (ke/ks). Modal response to a harmonic convected wave is greatest for all modes, except the first, when the ratios are both unity. For the first mode, the response is greatest when (u/a) approaches +∞ and (ke/ks) approaches 0 so that the product remains unity. The response is strongly affected by crossproduct terms, even though orthogonal eigenfunctions are used. Inclusion of the crossproduct terms in the calculations results in a mean‐square displacement that is less peaked at the center of the string but correspondingly higher toward the outer ends than if these terms had been neglected. The effect of the boundary flexibility is to increase the mean‐square displacement at all points of the string, and also to make the distribution of this displacement more uniform over the length.

European Experience with Sound‐Insulation Requirements

Ove Brandt

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 719-724 (1964); (6 pages) | Cited 1 time

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
Most of the world's major nations, with the exception of the United States of America, have sound‐insulation requirements in their building codes. The purpose of this paper is to describe the experience of several European countries with such requirements. Typical procedures in common use are discussed: there are several variations in the basic definition of sound insulation, the method of interpreting test results, and, finally, the method of influencing or controlling building practice. An important consideration is the information to be gained from various possible types of test. Experience indicates the desirability of three stages of testing for a new type of construction: (1) laboratory tests on individual components; (2) tests on a partial assembly of wall and floor sections; and (3) tests on the completed structure. At each stage, problems are usually found that had not been anticipated earlier.

Sound Insulation and the Apartment Dweller

T. D. Northwood

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 725-728 (1964); (4 pages)

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
Most of the existing sound‐insulation requirements are based on experience with traditional construction, and this is reflected in the shape of the standard grading curve. Since nontraditional constructions frequently have quite different sound‐insulation characteristics, the desired shape of insulation curve, i.e., the relative importance of the various frequency bands, becomes an important consideration. To gain insight on this point, the problem was approached by considering directly the activities and needs of apartment dwellers. The tentative conclusion is that the most common type of grading curves, including the ASTM Sound Transmission Class curve, are of approximately the correct shape for rating sound insulation between dwellings.

Impact‐Noise Recommendations for the FHA

T. J. Schultz

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 729-739 (1964); (11 pages) | Cited 1 time

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
Because of increasing complaints of disturbance from impact noise in multifamily dwellings, the Federal Housing Administration plans to include in their Minimum Property Standards some recommendations for the control of this noise. A study of the existing noise codes and several surveys of public reaction to household noise has led to (1) the recommendation of a criterion of acceptability for floor/ceiling constructions in multifamily dwellings; a listing of floor/ceiling structures commonly used in the U S A, classified as to their ability to meet the criterion, and (2) a set of recommendations and suggestions regarding important structural details. This paper gives the results of that study and tells how they were arrived at.

Owner's Viewpoint in Residential Acoustical Control

Frederick P. Rose

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 740-742 (1964); (3 pages)

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
Stress is laid on the lack of adequate acoustical treatment in the design and construction of multiple dwellings in the United States of America.

Integration of Energy at Threshold with Gradual Rise‐Fall Tone Pips

Peter J. Dallos and Wayne O. Olsen

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 743-751 (1964); (9 pages) | Cited 3 times

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
Short‐tone thresholds were tested with an array of ten stimuli so chosen to incorporate a wide range of parameter variations. It was shown that the average data could be very well fitted with the function (I−I0)T  =  k, where I is the stimulus intensity at threshold, I0 and k are constants, while T is the equivalent stimulus duration. This equivalent duration was derived for gradually rising and falling tone pips, and was shown to be computable as T  =  2r/3+P, where r is the rise‐fall time and P is the peak time. It was shown that the above model predicted individual thresholds with considerably greater accuracy than other alternative descriptions. The theoretical implications of the model are the existence of a definite lower limit of stimulus intensity (I0), below which the stimulus power does not contribute toward threshold recognition, and the constancy of the effective utilizable energy at threshold (k). This latter quantity did not vary more than 0.5 dB from stimulus to stimulus.

Effect of Monaural Fatigue upon Pitch Matching and Discrimination

D. N. Elliott, J. Sheposh, and L. Frazier

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 752-756 (1964); (5 pages)

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
Using binaural pitch‐matching data, the effect of moderate poststimulatory fatigue upon the ear's “tuning” was determined at several frequencies. In addition, the effect of the fatigue upon pitch discrimination was measured. Upward shifts in pitch were observed at TTS's of 20 dB at both 2800 and 5600 cps; however, the shift at 5600 cps is questionable since it was not statistically significant. From these data, Ruedi's observation that the direction of postfatigue pitch shifts reverses (decreases rather than increases) for frequencies above 4000 cps is questioned. There was limited evidence that fatigue results in poorer pitch discrimination; however, such effects were not marked. Possibly, monaural data would have resulted in more‐clearcut effects.

Pitch of High‐Pass‐Filtered Pulse Trains

Newman Guttman and J. L. Flanagan

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 757-765 (1964); (9 pages) | Cited 2 times

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
This experiment determined the pitch of mixed‐polarity pulse trains, high‐pass‐filtered at 2 and 4 kcps. It was found that pitch may be associated with pulse rate at rates higher than the limit of 150 pps found with unfiltered pulses. At frequencies higher than those supporting pulse‐rate pitch, some tendency to hear a pitch equal to the spectral difference frequency appears. Evidence for the difference‐frequency interpretation is the contrast in pitch of patterns equated for pulse number but possessing all‐harmonic and odd‐harmonic spectra. Comparison of the pitch results with a computer simulation of basiliar‐membrane displacements revealed some correlation of difference‐frequency pitch with displacement envelope. It is hypothesized that the high‐pass input‐filter slope combines with the natural‐membrane low‐pass characteristic to form a narrow passband. The envelope of membrane displacement at the passband site tends to contain a pitch‐significant frequency component equal to the difference frequency. It is furthermore suggested that a major source of the pitch of low‐frequency broad‐band periodic sounds is roughly the 400‐cps region of the basilar membrane.

Stimulus‐Oriented Approach to Detection

Lloyd A. Jeffress

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 766-774 (1964); (9 pages) | Cited 5 times

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
Distribution curves for amplitude (envelope), drawn for noise and for noise plus signal, provide the basis for determining the proportion of area (probabilities) lying above various “criterion” levels. Probability pairs P (y∣n) and P (y∣sn) for various criterion levels furnish the coordinates of points generating ROC curves, which, because of the skewness of the distributions, show a slight curvature when plotted on normal‐normal paper. This curvature (concave downward) provides a better fit to detection data obtained from rating‐scale experiments than do the straight lines obtained from normal curves. The ROC curves belong to a family derived through the theory of signal detectability for the ideal observer in the case where signal phase is unspecified. The fact that the distribution for noise‐plus‐signal amplitudes has, in general, a larger variance than that for noise alone explains why many experiments find the ratio of σsn to σn to be greater than unity. A detection measure d, derived from the two distribution curves, when plotted against signal amplitude, is a straight line over most of its course but bends in to the origin for weak signals. Its failure to touch the positive abscissa supports the TSD argument against the threshold hypothesis. A second curve, derived from this one, provides a convenient way of determining the signal required to yield a particular value of ds, when the signal that yields some other value of ds is known. Finally, the concept of “effective bandwidth” is developed, and provides a single parameter for use in fitting detection data. Data give some support for the notion that the auditory system adjusts its bandwidth in accordance with the duration of the signal.

Calibration of Audiometers

Alex E. Martens

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 775-778 (1964); (4 pages)

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
This paper considers the various techniques and equipment used in audiometer calibration. Sources of faulty performance in audiometers are pointed out and the methods of detection suggested. A complete laboratory calibration facility is described in some detail.
back to top
RSS Feeds

Erratum: Transfer Function of the Middle Ear [J. Acoust. Soc. Am. 35, 1526–1534 (1963)]

Aage R. Møller

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 779-779 (1964); (1 page)

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Abstract Unavailable

Light Diffraction by Ultrasonic Waves for Oblique Incidence

Walter G. Mayer

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 779-781 (1964); (3 pages)

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
The diffraction of light by progressive, sinusoidal ultrasonic waves in water is investigated experimentally for conditions where Raman‐Nath diffraction or Bragg reflections might occur. Results are given for frequencies between 3 and 12.3 Mc/sec and for angles between the direction of sound and light propagation within ±1° of normal incidence.

Comments on “Radiation Impedance of a Source near Reflectors” by R. V. Waterhouse

George C. Maling, Jr.

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 781-783 (1964); (3 pages)

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
The increase in acoustic power output of a constant‐strength point monopole caused by boundaries can be found directly from the value of the imaginary part of the reflected pressure at the source. Waterhouse obtained an expression for the power output of a source by assuming that the plane could be specified by a pressure‐reflection coefficient (R) that is Independent of the angle of incidence. It is shown here that for some geometries the power output is independent of the angular dependence of R. When the source is located over an infinite plane, the increase in acoustic power output can also be found by using admittance boundary conditions. Some solutions are presented for this configuration and are compared with the results obtained by Waterhouse.

Reply to Dr. Maling's “Comments on ‘Radiation Impedance of a Source near Reflectors’ by R. V. Waterhouse”

Richard V. Waterhouse

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 783-783 (1964); (1 page)

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Abstract Unavailable

On the Estimation of the Generalized Force due to Random Pressure and on Necessary Modes

Alan Powell

J. Acoust. Soc. Am. Volume 36, Issue 4, pp. 783-784 (1964); (2 pages)

Online Publication Date: 20 Jul 2005

Full Text: | Download PDF

Show Abstract
Under certain conditions of major practical interest, the double surface integral giving the generalized force due to a random pressure field for a mode of vibration can be reduced to the product of two double line integrals. For sinusoidal mode shapes, the double line integral further reduces to a single integral, easily evaluated for any correlation function. It is also pointed out that for cylindrical structures, lacking a boundary condition of zero deflection for the circumferential modes, the modes cos (nθ) and sin (nθ) must both be considered.
Page 1 of 2 Pages Next Page | Jump to Page
Close

Home Publications Meetings Contact ASA Site Map Back to Top

Copyright © Acoustical Society of America

close