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

Journal of the Acoustical Society of America

BROWSE VOLUMES

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

Apr 1974

Volume 55, Issue 4, pp. 695-891

Page 1 of 3 Pages Next Page | Jump to Page

Noise control versus shock and vibration engineering

Charles T. Morrow

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 695-699 (1974); (5 pages)

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
Noise control and shock and vibration engineering have many fundamentals in common and many analogous practical constraints. Yet, in many respects they tend to be opposite in methodology, philosophy, and past history. The present discussion is an attempt to present the point of view of the practicing engineer, in either field, who has some perspective on the historical origins of his art. It focuses on aspects that epitomize the practical objectives of such engineers plus any administrators, lawyers, etc., who may also be involved in team efforts. For noise control, the aspects chosen are establishment of regulations, monitoring, and design or other actions intended to bring about compliance with regulations. For shock and vibration engineering, they are establishment of environmental specifications to ensure reliability, environmental testing in accordance with these, and design or redesign to bring about compliance with test requirements and also (we hope) to bring about reliability without severe penalties in weight, schedule, or cost. This is not to say that these aspects in their barest sense represent all the technology or methodology that is pertinent, or even that these limited aspects will be treated comprehensively. It is almost self‐evident that the Acoustical Society of America should and does maintain beneficial relationship with medical, psychological, mechanical engineering, and other societies that report their particular developing lore of fundamentals and some practical information from their particular viewpoint. The Acoustical Society is an important part of this spectrum by virtue of its interdisciplinary coverage, extending through materials, dynamics, sound, instrumentation, and electronics to speech and hearing. But it is also worthwhile for the ASA, by whatever means are available, to sample the flavor of various disciplines as unified and value‐weighted in accordance with typical practical objectives. For this reason, the developing beneficial relationships with the Institute of Noise Control (INCE) and the Shock and Vibration Information Center (SVIC) will become increasingly important.

Wave propagation in elastic media with a periodic array of discrete inclusions

R. M. Christensen

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 700-707 (1974); (8 pages)

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
This study concerns the propagation of time harmonic waves in a continuous medium in which is embedded a three‐dimensional periodic array of discrete inclusions. Both phases are taken to be elastic, and the symmetry characteristics of the combination are of the type of cubic crystals. A perturbation method of analysis is employed to obtain the steady‐state periodic wave solution where full account is given to the multiple interacting reflections of shear and dilatational waves. When the solution is specialized to the case of constant moduli with only the density being variable, an attenuation factor for transient waves is extracted heuristically.

Transient fluid reaction on a baffled plane piston of arbitrary shape

Oscar A. Lindemann

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 708-717 (1974); (10 pages)

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
The inverse Laplace transform of the frequency‐dependent radiation impedance of a baffled piston, i.e., its impulse response, is a function which is more directly related to the geometry of the piston than the impedance itself. It is here shown how this function can be described in terms of a finite pulse called the characteristic pulse, whose shape depends on that of the piston, and that its evaluation depends on a relatively simple integration around the piston's contour. A number of examples show that the characteristic pulse can be evaluated exactly for certain piston shapes. Geometrical features of the piston's shape, such as corners, have a predictable effect on the characteristic pulse, and hence on the radiation impedance; some of these fundamental relationships are derived in the form of simple theorems.

Wave propagation in anisotropic bars of rectangular cross section. III

Nicholas J. Nigro and Patrick A. O'Malley

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 718-723 (1974); (6 pages)

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
The Ritz method is used to obtain the dispersion curves for the problem of torsional‐wave propagation in anisotropic bars of infinite length and rectangular cross section. The first three dispersion curves are presented for orthotropic, tetragonal, hexagonal, cubic, and isotropic bars with several ratios of width to depth. The displacements corresponding to various dimensionless phase velocities are presented and discussed in some detail. The investigation is an extension of previous work [J. Acoust. Soc. Am. 40, 1501 (1966); 43, 958 (1968); 46, 639 (1969)] in elastic‐wave propagation.

An exact expression for the Lommel‐diffraction correction integral

Peter H. Rogers and A. L. Van Buren

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 724-728 (1974); (5 pages) | Cited 12 times

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
A number of authors have obtained diffraction corrections for a circular piston source by numerical or graphical integration of an approximate expression for the piston field attributable to E. Lommel [Abh. Bayer. Akad. Wiss. Math.‐Naturwiss. Kl. 15, 233 (1886)]. Lommel's expression gives the piston field in terms of trigonometric functions and Lommel functions of two variables. It is shown here that the required integral of Lommel's expression can be evaluated analytically to obtain a simple closed‐form expression for the diffraction correction. The extrema of this expression are obtained as roots of simple transcendental equations, and approximation formulas for these roots are given. It is also shown that the same expression can be obtained by taking the limit as ka → ∞ (k is the wavenumber and a is the piston radius) of Williams's exact integral expression [J. Acoust. Soc. Am. 23, 1–6 (1951)] for the diffraction correction. Finally, it is shown both analytically and by comparison with numerical values for Williams's exact expression that this simple closed‐form expression is a good approximation for the diffraction correction at all distances from the source provided that (ka)1/2 ≫ 1.

Ray‐acoustic intensity in a moving medium. I

Robert J. Thompson

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 729-732 (1974); (4 pages) | Cited 2 times

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
A quite general expression for ray‐acoustic intensity in terms of ray trajectories in a moving medium is derived. The speed of sound and the three components of the velocity of the medium can be functions of the three space variables. They can even depend on time. The only restriction is that the speed of the medium must be subsonic. The fact that the sound source may not radiate energy uniformly in all directions is taken into account. It is shown that for the special case of a motionless medium the results reported here reduce to some known results.

Ray‐acoustic intensity in a moving medium. II. A stratified medium

Robert J. Thompson

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 733-737 (1974); (5 pages) | Cited 1 time

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
Techniques are developed for computing ray‐acoustic intensity in a horizontally stratified moving medium. Under the assumptions that the speed of sound and the components of the wind vector are piecewise linear functions, it is shown that an exact expression for the intensity can be obtained by patching together functions with the aid of a table of integrals. For the general horizontally stratified moving medium, the ray paths and the intensity can often be approximated by numerically solving a system of ordinary differential equations.

Reflection and transmission of Rayleigh waves by the edge of a deposited thin film

Tsukasa Yoneyama and Shigeo Nishida

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 738-743 (1974); (6 pages) | Cited 5 times

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
The reflection and transmission of Rayleigh waves by the edge of an isotropic thin film deposited on an isotropic substrate is solved within the first‐order approximation relying on the Wiener‐Hopf technique under the assumption that the film is thin enough compared to the wavelength. Straight‐crested Rayleigh waves are assumed to impinge on the edge of the film perpendicularly from the unplated side of the substrate. In formulating the problem mathematically, Tiersten's boundary condition is employed to take into account the effects which the deposited film imposes on the elastic waves in the substrate. Expressions for the radiation coefficients of both of the bulk waves, longitudinal and transverse, and for the reflection coefficient of the Rayleigh wave are derived and evaluated numerically for gold, aluminum, nickel, and copper films deposited on the fused‐silica substrate. It is found that the radiation coefficients, especially the one for the transverse bulk wave, exceed the reflection coefficient by a factor of 10 or more in magnitude. The reflection and transmission of the Rayleigh wave is influenced mainly by the shear velocity and shear modulus μ′ of the film material, whereas the Lamé constant λ′ of the film does not have as much effect on both the reflection and transmission.

Frequency smearing of sound forward‐scattered from the ocean surface

M. Vertner Brown and George V. Frisk

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 744-749 (1974); (6 pages) | Cited 2 times

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
The results of an open sea experiment are presented in which CW acoustic signals generated by an omnidirectional source and forward‐scattered by the ocean surface were measured. The statistics of the surface waves were simultaneously measured by a surface sensing buoy. It is found that for acoustic frequencies in the range of 100–500 Hz and for conditions of small surface roughness, the acoustic spectrum contains the discrete carrier frequency component with sidebands symmetrically positioned about the carrier, as predicted theoretically. The sidebands are directly related to the surface wave spectrum through a response function, which in general depends on both the acoustic carrier and surface wave frequencies. The experimental response function is compared with response functions predicted theoretically by Roderick and Cron, Parkins, and Williams. In addition, for conditions of moderate roughness, marked asymmetry in the acoustic spectra and strong spectral components that are not prominent in the surface spectra are found.

Spatial variability of underwater ambient noise at the Arctic ice‐water boundary

O. I. Diachok and R. S. Winokur

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 750-753 (1974); (4 pages) | Cited 1 time

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
Quasisynoptic measurements were made to determine the spatial variability of ambient noise at the Arctic ice‐water boundary over a frequency range from 100 to 1000 Hz. The results of this investigation show that the ice‐water boundary acts as a spatially well‐defined source of ambient noise with measured noise levels near a compact edge about 12 dB higher than open water levels and about 20 dB higher than levels far in the ice field. Measured noise levels near a diffuse ice edge were about 4 dB higher than open water levels, and about 10 dB higher than levels far in the ice field. The relatively high noise levels at the ice edge are probably generated by wave and swell interactions with individual ice floes.

Infrasonic and low‐frequency ambient noise measurements on the Grand Banks

Anthony J. Perrone

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 754-758 (1974); (5 pages)

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
Infrasonic and low‐frequency ambient noises were investigated using a bottom‐mounted omnidirectional hydrophone located in 614 fm of water on the Grand Banks. Data were recorded continuously on magnetic tape from 20 to 28 July. Ten‐second average levels for 25 contiguous 1/3‐octave bands between 1 and 250 Hz were computed for the entire eight‐day period. Hourly averages were then computed from the 10‐sec values. Autocorrelations of ambient‐noise level and wind speed, as well as cross correlation of ambient‐noise level with wind speed, are presented. In the 4–250‐Hz range, the measured ambient‐noise spectra are produced predominantly by large fishing vessels in the general area of the hydrophone; in the 1–4‐Hz range, a relatively strong wind‐speed dependence is observed. The high values of standard deviation (as a function of frequency) are suspected to be caused by the varying proximity of the few ships in the area to the hydrophone. The correlation coefficient of wind speed to sea noise is variable and directly dependent on the wind‐speed distribution and the amount, type, and location of shipping during the measurement period.

A correlation technique for determining the self‐ and mutual‐radiation impedances of transducers in an array

Anthony J. Rudgers

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 759-765 (1974); (7 pages)

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
Linear‐system analysis is applied to a transducer array and an input‐output relation is established from which the self‐ and mutual‐radiation impedances of the array transducers may be determined. The radiation impedances are determined by applying currents at the electrical terminals of the array transducers that are derived from multicorrelated time series and by measuring the crosscorrelation between these currents and the voltages appearing at the electrical terminals. Since only electrical quantities are involved, it is possible to obtain the radiation impedances of a transducer array of very general character because no knowledge of the nature of the acoustic field of the array or of the mechanical motion of its radiating surfaces is needed. So long as the transducer‐array system is linear and of finite size, it may consist of transducers of dissimilar types, having arbitrary shapes and sizes, with normal velocities that are not necessarily uniform across the transducer faces. Moreover, the transducers may be located in one or more baffles of arbitrary shape and acoustic characteristics and one or more reflectors— these, too, being of arbitrary shape, size, and acoustic characteristics—may be located in the vicinity of the radiating array.

Determination of electron mobilities in thin metal films from the attenuation of elastic surface waves

P. Bierbaum

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 766-744 (1974); (-21 pages) | Cited 5 times

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
An elastic surface wave propagating on a piezoelectric substrate on which a metal film is being deposited is attenuated as a result of the interaction between the wave and charge carriers in the film. This attenuation was measured for various metals and substrate temperatures. It was shown that the experiments agree closely with a theoretical model if an electron diffusion term is retained and related to the Fermi energy of the metal under consideration. It thus becomes possible to determine the product of electron mobility and Fermi energy from the measured maximum attenuation. The assumption that bulk Fermi energy would apply to the films proved correct except in the case of the semi‐metals tin and bismuth, and electron mobilities were obtained which agreed with published values.

Kinetic theory of sound propagation in gaseous mixtures. I. Two‐fluid 5‐moment, 13‐moment, and Navier‐Stokes Theories

Francis J. McCormack and David E. Craven

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 775-782 (1974); (8 pages)

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
Plane sound wave propagation in binary mixtures of monatomic gases is studied using sets of two‐fluid 5‐moment, 13‐moment, and Navier‐Stokes equations. Numerical solutions are obtained for the absorption coefficient and propagation speed as a function of the ratio of frequency to pressure. The physical parameters upon which the solutions depend are the molecular mass and number density ratios and the ratios of the force constants in the Maxwell‐molecule intermolecular force law. The different roots of the dispersion relations are discussed, and the 13‐moment and Navier‐Stokes solutions are presented for the sound mode in He‐Ar mixtures of varying relative concentration. These agree very favorably with the existing experimental data and the previous two‐fluid theory of Goldman, especially the Navier‐Stokes solutions. In addition, absorption curves for He‐Ne and He‐Xe are presented. It is found that the two‐fluid 13‐moment and Navier‐Stokes solutions for each mixture considered behave qualitatively very much like the corresponding solutions for a simple gas, and consequently share the same successes and failures. Also, briefly discussed is a more refined model equations approach (of which the present theories can be considered the first approximation), the details of which will be presented in a later paper in this series.

Ultrasonic spectroscopy applied to double refraction in worked metals

Emmanuel P. Papadakis

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 783-784 (1974); (2 pages)

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
An experiment has been performed showing that ultrasonic spectroscopy can be used to study texture in worked metals and other textured polycrystals. Echoes from a broadband shear transducer polarized at 45° between two characteristic directions in a rolled aluminum specimen showed nulls in their spectrum corresponding to differences of (2 n − 1)π in phase between the components of the wave amplitude resolved along the characteristic directions. From the frequencies of the nulls, the fractional velocity difference Δv/v was computed to be 0.021, a reasonable value for aluminum with moderate texture. Ultrasonic spectroscopy is particularly useful to study texture when the first echo contains several nulls, i.e., n > 1 in the phase difference (2n − 1)π.

Hypersound speeds in carbon disulfide, acetone, and benzene at high pressure

J. H. Smith, L. M. Peterson, D. H. Rank, and T. A. Wiggins

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 785-789 (1974); (5 pages) | Cited 2 times

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
Hypersound speeds have been measured in carbon disulfide, acetone, and benzene by means of optical mixing employing stimulated Brillouin scattered light at 27°C in the pressure range from 1 to 1000 atm. Ratios of the specific heats at constant pressure and volume were also deduced. In carbon disulfide the dispersion between hypersonic and ultrasonic frequency was essentially constant over the pressure range studied, In acetone, hypersound speeds increased linearly with increase in pressure. In benzene, complete vibrational relaxation does not take place above 400 atm. The hypersound speeds remained essentially constant at higher pressures indicating a decrease in the ratio of specific heats that is not observed at ultrasonic frequencies.

Probability density of a frequency‐modulated sound signal in a reverberant enclosure

Paul M. Gammell and Richard Waterhouse

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 790-794 (1974); (5 pages)

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
One of the statistics of a random sound field in a reverberant enclosure is the distribution in time of the instantaneous sound pressure at a fixed point in space. Theoretical and experimental results are presented showing that this distribution tends toward Gaussian if the frequency modulated source contains a large number of sidebands at frequencies for which the responses of the enclosure are uncorrelated. The smallest frequency interval required for the responses to be uncorrelated is obtained from the autocorrelation function of the room response, which Schroeder showed to be related to the decay time of the room. It is the number of sidebands yielding substantially uncorrelated responses, rather than the number of sidebands having appreciable power, that determines the distribution.

Effects of intense auditory stimulation: hearing losses and inner ear changes in the chinchilla

Ivan M. Hunter‐Duvar and Göran Bredberg

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 795-801 (1974); (7 pages)

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
Following determination of normal audiograms, eight chinchillas were exposed to intense acoustic stimuli which produced permanent threshold shifts (PTSs). Four of the animals were exposed to narrow‐band noise at an overall intensity of 123 dB for 15 minutes. The other four animals were exposed to a 1000‐Hz tone at an intensity of 120 dB for durations sufficient to produce PTSs. Final thresholds were determined five weeks after exposure, after which animals were sacrificed and cochleas were fixed and prepared as surface specimens. Counts of missing or severly damaged hair cells were made for each cochlea. Animals exposed to noise had hearing losses ranging from 14 dB to greater than 45 dB. Anatomical damage ranged from no visible damage for the animal with the 14 dB loss to very severe damage for the animal with the 45‐dB loss. Animals exposed to the 1000‐Hz stimulus showed losses from 22 dB to greater than 45 dB. Lesions for this group ranged from 0.5 to 1.5 mm. The 12‐min pure‐tone exposure of chinchillas produced greater losses than seen in squirrel monkeys exposed 12 hours to the same stimulus.

Auditory filter shape

Roy D. Patterson

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 802-809 (1974); (8 pages) | Cited 10 times

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
Threshold for a pulsed tone was measured as a function of its distance in frequency from the edge of a broad band of noise with very sharp skirts. Tone frequency was held constant at 0.5, 1.0, 2.0, 4.0, or 8.0 kHz while the position of the noise edge was varied about the frequency of the tone. The spectrum level of the noise was 40 dB. As expected, tone threshold decreased as the distance between the tone and the noise edge increased, and the rate of decrease was inversely related to tone frequency. The data were used in conjunction with a simple model of masking to derive an estimate of the shape of the auditory filter. A mathematical expression was found to describe the filter, and subsequently, this expression was used to predict the results reported by several other investigators.

Human auditory thresholds during deep, saturation helium‐oxygen dives

William G. Thomas, James Summit, and Joseph C. Farmer

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 810-813 (1974); (4 pages)

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
Air‐conduction and bone‐conduction thresholds were derived on 33 different divers on eight saturation dives in helium‐air between 300 and 1000 ft. A total of 400 air‐conduction and 300 bone‐conduction audiograms were given at 26 different depths during compression and decompression. The results indicate a reversible, depth‐related conductive hearing loss. The shape of the audiometric function and absolute amount of hearing loss are somewhat different from data reported in hyperbaric air.

Thresholds of audibility for very low‐frequency pure tones

Norman S. Yeowart and Margaret J. Evans

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 814-818 (1974); (5 pages) | Cited 2 times

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
This paper presents new binaural‐hearing‐threshold data obtained (a) by an earphone method over the frequency range 5–100 Hz and (b) by a whole body chamber method over the range 2–20 Hz. The results obtained are in excellent agreement with recent reported data. The binaural to monaural listening advantage appears to remain at 3 dB throughout the frequency range. A good approximation to the binaural threshold of hearing may be formed by lines from the point 92.0 dB SPL at 15.5 Hz with slopes of 12.3 dB/octave for frequencies below 15.5 Hz and 22.2 dB/octave above.

Some cues for syllable juncture perception in English

William M. Christie, Jr.

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 819-821 (1974); (3 pages) | Cited 1 time

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
Most previous acoustic research on syllable juncture phenomena has used as stimuli recordings of natural speech. From this research it has been possible to suggest that certain differences observed in spectrograms of the recordings might cue the differences in the perceived location of the syllable boundary, but confirmatory tests with synthetic stimuli have been lacking. This experiment uses synthetic stimuli to examine intervocalic /st/ clusters to determine the effects of formant transitions onto the /s/, silence between the end of the /s/ noise and the /t/ burst, and aspiration on the /t/ in determining the location of syllable boundaries in English. Formant transitions appear to have little or no effect on the boundary, but silence and aspiration both affect perception of the boundary location. The fact is noted that the aspiration on the /t/ is a feature of allophonic alternation in English. A proposal made earlier by Lehiste that allophonic alternations can carry structural information is thus confirmed by this experiment. Some suggestions for further research are appended.

How does a mynah bird imitate human speech?

Dennis H. Klatt and Raymond A. Stefanski

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 822-832 (1974); (11 pages) | Cited 2 times

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
Broad‐band spectrograms and computer‐generated spectra have been obtained of a trained Indian Hill mynah bird and its tutor each saying seven English sentences composed of four to 12 phonetic segments. Comparisons of sound spectrograms indicate that the bird is able to produce good approximations to virtually any spectral or temporal detail, although energy in frequencies below about 700 Hz (in the range of the first formant) is attenuated by about 10–20 dB relative to human spectra. Fundamental frequency (F0) contours, formant transitions, and turbulent noise spectra for fricatives and plosive bursts are especially well imitated. Contour shapes are better preserved than absolute formant or F0 values. Some vowel spectra have clear formant patterns but many have multiple resonances and formant splitting effects that cannot be accounted for in terms of an acoustic tube model of formant generation. A new description of the behavior of the mynah syrinx is proposed to account for the observed acoustic patterns. One of the paired external labia in the syrinx is implicated as the source of voicing energy (analogous to the human vocal cords). Some or all of the formant resonances are produced by exciting the mechanical resonant modes of the internal tympaniform membrane in the syrinx. The five pairs of intrinsic muscles that are associated with the syrinx are capable of controlling membrane tensions and regulating the position of the external labia in the syringeal airways during sound production.

Talker differences as they appear in correlation matrices of continuous speech spectra

K.‐P. Li and G. W. Hughes

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 833-837 (1974); (5 pages)

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
The properties and measurement of intertalker and intratalker variability among correlation matrices derived from spectra of continuous speech are described. Measures of difference between two matrices are applied to quantify talker variability. These measures of difference are consistently less for intratalker data than for intertalker comparisons. For a population of 30 talkers, the distributions of these differences show about 1% overlap to confound absolute identification of a given talker. The effects of spectral shaping and sample size are discussed, and applications to talker identification and normalization schemes suggested.

Articulatory interpretation of the “singing formant”

Johan Sundberg

J. Acoust. Soc. Am. Volume 55, Issue 4, pp. 838-844 (1974); (7 pages) | Cited 16 times

Online Publication Date: 12 Aug 2005

Full Text: | Download PDF

Show Abstract
The “singing formant” is a high spectrum envelope peak near 2.8 kHz characteristic of vowel sounds produced in male Western opera and concert singing. An acoustical model of the vocal tract is capable of generating such a peak provided that three conditions are met: (1) The cross‐sectional area in the pharynx must be at least six times wider than that of the larynx tube opening. If so, the larynx tube is acoustically mismatched with the rest of the vocal tract, and an extra formant is added to the vocal tract transfer function. (2) The sinus Morgagni must be wide in relation to the rest of the larynx tube. This may tune the frequency of the extra formant to a value between the frequencies of the third and fourth formants in normal speech. (3) The sinus piriformes must be wide. This reduces the frequency of the fifth formant to about 3 kHz. X‐ray studies of a raised and lowered larynx showed that these three conditions may be fulfilled when the larynx is lowered. Thus, the larynx lowering, typical of male professional singing, seems to explain the “singing formant” and other formant frequency differences between normal speech and male professional singing.
Page 1 of 3 Pages Next Page | Jump to Page
Close

Home Publications Meetings Contact ASA Site Map Back to Top

Copyright © Acoustical Society of America

close