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Journal of the Acoustical Society of America

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Dec 1973

Volume 54, Issue 6, pp. 1433-1768

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Ranking the impact sound transmission of wood‐framed floor‐ceiling assemblies

Victor E. Belmondo, Thomas B. Heebink, and Frank H. Brittain

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1433-1441 (1973); (9 pages)

Online Publication Date: 12 Aug 2005

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A masking procedure has been developed to rank apartment floor‐ceiling systems in order of their resistance to the transmitted sound of footfalls. Results obtained subjectively show that the current international standard for rating impact noise transmission using a tapping machine incorrectly ranks some wood‐framed floor‐ceiling systems. When the described procedure is used to mask tapping machine noise, the floors are also incorrectly ranked. This inadequacy continued even though low frequencies, below the 89‐Hz cutoff of the 100‐Hz 1/3 octave, were included in the masking procedure. Because the masking procedure described is subjective, the problems associated with the development of an objective test are also discussed. A simple objective test method is suggested for future development.

Monte Carlo applications to acoustical field solutions

John Kenneth Haviland and Balakrishna D. Thanedar

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1442-1448 (1973); (7 pages) | Cited 1 time

Online Publication Date: 12 Aug 2005

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The Monte Carlo technique is proposed for the determination of the acoustical pressure‐time history at chosen points in a partial enclosure, the central idea of this technique being the tracing of acoustical rays. A statistical model is formulated and an algorithm for pressure is developed, the conformity of which is examined by two approaches and is shown to give the known results. The concepts that are developed are applied to the determination of the transient field due to a sound source in a homogeneous medium in a rectangular enclosure with perfect reflecting walls, and the results are compared with those presented by Mintzer based on the Laplace transform approach, as well as with a normal mode solution. In contrast with these, the Monte Carlo method is not restricted to the case of perfectly reflecting walls, since absorptive walls can be handled. Possible future developments are indicated which would, it is believed, make the Monte Carlo method a valuable tool when boundary conditions are complex or when the medium is inhomogeneous.

Dilational‐mode sound transmission in sandwich panels

C. P. Smolenski and E. M. Krokosky

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1449-1457 (1973); (9 pages) | Cited 2 times

Online Publication Date: 12 Aug 2005

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Dilational vibration modes have been shown to produce an undesirable “coincidence type” response in the sound‐transmission spectrum of lightweight‐core sandwich panels in the medium to high‐frequency range. In particular, it was found that the dilatational coincidence region often occurs at considerably lower frequencies than those coincidence effects produced by flexural vibration. The governing characteristic frequency equations were developed by employing the Rayleigh‐Ritz Energy Principle for a sandwich panel with variable dimensions and properties. The present solution also employs a general strain energy relation without restricting the skin materials to be identical. Eight characteristic natural frequencies representing dilatational, flexural, and longitudinal vibration were determined for the fundamental as well as higher order modes as a function of panel dimensions and material properties. Throughout this study particular attention was given to the influence of core properties on the dilatational natural frequencies. Experimental panels with various face and core materials were tested under random incidence sound‐transmission conditions and found to compare favorably with the theoretical predictions.

Theory of binaural interaction based on auditory‐nerve data. I. General strategy and preliminary results on interaural discrimination

H. Steven Colburn

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1458-1470 (1973); (13 pages) | Cited 32 times

Online Publication Date: 12 Aug 2005

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We discuss initial research on a model of binaural hearing in which the peripheral transduction from acoustical waveforms to firing patterns on the auditory nerves is explicitly described. In most of this initial research, attention is focused on interaural time discrimination, and the processing that follows the peripheral transduction (the central processing) is assumed to be ideal. By imposing limitations on the central processing and computing the consequences for performance, we find that performance at least as good as experimentally observed performance can be achieved with central processing that is substantially restricted.

Consequences of peripheral frequency selectivity for nonsimultaneous masking

H. Duifhuis

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1471-1488 (1973); (18 pages) | Cited 19 times

Online Publication Date: 12 Aug 2005

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The frequency selectivity of the peripheral ear (e.g., at the VIIIth nerve level) is so acute that onset and offset transients in responses to short signals produce a nonnegligible extension of the signal duration. Thus, peripheral excitation patterns produced by signals which were separated in time can overlap and thereby mask each other. We refer to this type of masking as transient masking. Published data on nonsimultaneous masking and the results of two new experiments are compared with the masking that may be expected from filter transients. It is concluded that backward masking is mainly due to interactions at the level of the filter outputs, and that in forward masking, in addition to a short‐term component, a long‐term component is distinguishable. The latter has an exponential decay with a time constant of approximately 75 msec, and is probably related to physiological adaptation effects.

Some monaural and binaural facets of median plane localization

Mark B. Gardner

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1489-1495 (1973); (7 pages) | Cited 11 times

Online Publication Date: 12 Aug 2005

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Recent studies, together with others dating back as far as 1851, leave little doubt that the cavities and convolutions of the pinnae play an important role in the localization of signals that originate in the median plane. Less clearly understood, however, is the nature of the clues that are utilized in arriving at a localization decision. Results of the present study indicate that, insofar as localization in the anterior sector of the median plane is concerned, clues associated with the cavities of the pinna have an important monaural component. Binaural reception also plays a significant role including confining the apparent location of the resultant image within, or near, the median plane. Such a centralizing influence is an essential requirement for optimizing this type of localization. Clues of a secondary nature were found to be associated with the range of frequencies between about 0.7 and 3.5 kHz.

An optimum processor theory for the central formation of the pitch of complex tones

Julius L. Goldstein

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1496-1516 (1973); (21 pages) | Cited 66 times

Online Publication Date: 12 Aug 2005

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A comprehensive theory is formulated for the central formation of the pitch of complex tones, i.e., periodicity pitch [Schouten, Ritsma, and Cardozo, J. Acoust. Soc. Amer. 34, 1418–1424 (1962)]. This theory is a logical deduction from statistical estimation theory of the optimal estimate for fundamental frequency, when this estimate is constrained in ways inferred from empirical phenomena. The basic constraints are (i) the estimator receives noisy information on the frequencies, but not amplitudes and phases, of aurally resolvable simple tones from the stimulus and its aural combination tones, and (ii) the estimator presumes all stimuli are periodic with spectra comprising successive harmonics. The stochastic signals representing the frequencies of resolved tones are characterized by independent Gaussian distributions with mean equal to the frequency represented and a variance that serves as free parameter. The theory is applicable whether frequency is coded by place or time. Optimum estimates of fundamental frequency and harmonic numbers are calculated upon each stimulus presentation. Multimodal probability distributions for the estimated fundamental are predicted in consequence of variability in the estimated harmonic numbers. Quantification of the variance parameter from musical intelligibility data in Houtsma and Goldstein [J. Acoust. Soc. Amer. 51, 520–529 (1972)] shows it to be dependent upon the frequency represented and not upon other stimulus frequencies. The quantified optimum processor theory consolidates known data on pitch of complex tones.

A system of nonlinear differential equations modeling basilar‐membrane motion

Duck On Kim, Charles E. Molnar, and Russell R. Pfeiffer

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1517-1529 (1973); (13 pages) | Cited 5 times

Online Publication Date: 12 Aug 2005

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A phenomenological model for displacement of a point on the basilar membrane is developed by formulating a system of nonlinear differential equations: mathi(t) + 2Di[1 + ηmathi2(t)]mathi(t) + ω0i2xi(t)  =  Cxi−1(t), for i = 1, 2, …, 10, where x0(t) is the input (stapes displacement) and x10(t) is the output. This model, which behaves effectively linearly at low levels and nonlinearly at high levels, shows that a single nonlinear system is adequate to account for the following frequency‐dependent nonlinear phenomena of the peripheral auditory system: (1) limiting of the output level; (2) decrease of Q with increasing input level; (3) decrease of the most effective frequency with increasing input level; (4) changes in phase angle of the output with input level; (5) changes in shape of the click response waveform with input level; (6) two‐tone suppression with f1 = CF and f2 > CF; (7) generation of the combination tone 2f1 − f2 in response to two tones f1 < f2); (8) “amplitude” nonlinearity in response to click pairs; and (9) “temporal” nonlinearity in response to click pairs. The success of the model in reproducing phenomena observed in basilar‐membrane motion (1–3), as well as in responses of single cochlear nerve fibers (1–9), suggested that all of these phenomena may occur in basilar‐membrane motion. As predicted by the model, direct observations of the presence of phenomena 4, 5, and 6 in basilar‐membrane motion have been recently reported.

Critical masking interval: a temporal analog of the critical band

M. J. Penner and Edward Cudahy

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1530-1534 (1973); (5 pages) | Cited 3 times

Online Publication Date: 12 Aug 2005

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The critical masking interval, the time period during which noise is effective in masking a brief click, was measured in two independent experiments. The first paradigm was the temporal analog of Fletcher's critical band experiment. That is, the click was presented in the temporal center of the noise, and its threshold was measured as the masker duration was varied. The second paradigm investigated the temporal analog of Greenwood's [J. Acoust. Soc. Am. 33, 484–502 (1961a)] masking experiment; that is, a click was moved temporally through the noise burst. The two paradigms yielded similar numerical estimates of the critical masking interval. Further, the critical masking interval was not greatly affected by the stimulus' bandwidth.

Recovery from sound exposure in auditory‐nerve fibers

Eric Young and Murray B. Sachs

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1535-1543 (1973); (9 pages) | Cited 5 times

Online Publication Date: 12 Aug 2005

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The discharge rate of single auditory‐nerve fibers to tone bursts was measured after exposure to continuous tones. Both the exposure tone and the test tone bursts were at the fiber's characteristic frequency. Following exposure, the discharge rate to the test bursts is transiently depressed. For moderate exposures (180 sec or less in duration and less than 80 dB SPL), the recovery of discharge rate to the preexposure level is well described by a single rising exponential. The time constant of the recovery increases as the level or duration of the exposure increases; time constant decreases as the level of the test bursts is increased. For all exposure and test conditions employed, time constants were in the range 1–30 sec. The relevance of these data to hypotheses about the mechanisms of adaptation in the auditory periphery is discussed.

Recovery of detection probability following sound exposure: comparison of physiology and psychophysics

Eric Young and Murray B. Sachs

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1544-1553 (1973); (10 pages) | Cited 1 time

Online Publication Date: 12 Aug 2005

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Detection probability for 1‐kHz test tone‐bursts was estimated at 1‐sec intervals following exposure of subjects to a 1‐kHz continuous tone. Immediately after the exposure tone, detection probability is depressed. Recovery to preexposure probability is well fit by a single rising exponential function. These psychophysical data are compared with the recovery of discharge rate in single fibers of the cat's auditory nerve following similar exposures. For both sets of data the time constant of recovery decreases with increasing test tone‐burst level; the decrease is significantly faster for detection probability recovery than for recovery of discharge rate. This difference can be accounted for by a simple model relating discharge rate in ensembles of auditory‐nerve fibers to detection probability. Whereas the recovery time constant of discharge rate increases monotonically with exposure level, the recovery time constant of detection probability increases up to about 40 dB SPL and then decreases as exposure level is increased. We could not explain this difference on the basis of existing data.

On the mechanism of sound production in organ pipes

Samuel A. Elder

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1554-1564 (1973); (11 pages) | Cited 7 times

Online Publication Date: 12 Aug 2005

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It is shown that both the Cremer‐Ising and Coltman mechanisms for sound production in organ pipes are comprehended by a more general approach, based on conservation of linear momentum. By calculating force per unit area exerted by the jet on a control volume containing the mixing region, and equating this to the difference in pressure along the pipe axis, it is possible to derive an expression for acoustic particle velocity in the standing wave as a function of the jet driving flow spectrum. The momentum model of the jet‐pipe interaction is able to explain the Coltman radiation symmetry effect, and also accounts for the role of entrained air in sound production. Additional spectral interaction terms, not previously noted, are found to play a significant role in the production of sound‐pressure fluctuations in the pipe. The fluctuating lift force at the edge is found to contribute to the sustenance of the pipe‐cavity oscillation below resonance, opposing it above resonance. In the near vicinity of the resonant frequency, edgetone effects are relatively small.

Noise propagation in cellular urban and industrial spaces

Huw G. Davies and Richard H. Lyon

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1565-1570 (1973); (6 pages) | Cited 4 times

Online Publication Date: 12 Aug 2005

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The effect of multiple barriers on the propagation of noise in urban and industrial environments is described by a cell model. The cell boundaries are formed by walls, machinery, etc., and each cell contains noise sources. The noise field both within and outside the souce region is discussed. A comparison with the results of previous investigations shows that the cell model correctly predicts the residual background level in traffic‐free zones in urban areas.

Unified analysis of fan stator noise

Donald B. Hanson

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1571-1591 (1973); (21 pages)

Online Publication Date: 12 Aug 2005

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A theory is developed which predicts the acoustic radiation of an axial‐flow fan stator due to interaction with rotor viscous wakes. Calculations are compared in detail with experimental data. Both the harmonic and broadband noise‐spectrum components are calculated from a unified model using methodology from the theories of random pulse amplitude modulation, PAM, and pulse position modulation, PPM. The stator is modeled as a circular array of pulsed dipoles. The amplitude and arrival time of each pulse are random variables whose means correspond to the values calculated from harmonic rotor‐stator interaction theory. The standard deviations of these random variables are measures of the turbulence levels in the blade wakes. For the model proposed the solution is exact: when PAM is imposed on a periodic stator source, new broadband energy is generated whose spectrum shape is similar to the envelope of harmonics at high frequencies and the harmonic radiation is unchanged; however, when PPM occurs, new broadband energy is radiated but at the expense of harmonic energy. At frequencies significantly above duct cutoff it is shown for a fixed stator solidity that the spectrum is essentially independent of the number of stator vanes.

Theoretical prediction of sound attenuation in acoustically lined annular ducts in the presence of uniform flow and shear flow

Sung‐Hwan Ko

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1592-1606 (1973); (15 pages) | Cited 1 time

Online Publication Date: 12 Aug 2005

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An investigation is made of the sound attenuation in a lined annular duct with flow. The eigenvalue equation in the presence of uniform flow is derived by matching the radial component of the particle displacement and acoustic pressure across a vortex sheet located an infinitely small distance from the facing sheet of an acoustic lining. The eigenvalue equation in the presence of shear flow is developed by matching the acoustic pressure and the radial component of the particle displacement at the interface between the regions of uniform flow and shear flow. Theoretical prediction of the sound‐attenuation spectrum is based on an acoustic‐energy flow in which the effect of the mean flow is taken into account. The results presented in this paper are limited to those which are typical for the geometry of an annular duct. Effects of mean flow Mach number, boundary‐layer refraction, and acoustic impedance on the sound attenuation for a given duct configuration are found to be similar to those in rectangular‐ and circular‐duct problems.

A model for vocal cord excitation

V. Gupta, T. A. Wilson, and G. S. Beavers

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1607-1617 (1973); (11 pages) | Cited 4 times

Online Publication Date: 12 Aug 2005

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This paper reports the results of an experimental and analytical investigation of a possible mechanism for exciting vibrations of the vocal cords. In order to test various approximations for describing the flow past the vocal cords and to demonstrate the importance of the upstream impedance in the excitation mechanism, the vocal cords are first represented by the simplest possible model, namely a simple vibrator of fixed shape. It is shown that if the pressures at the upstream and downstream ends of the channel formed by the vibrator wall are constant, the aerodynamic forces take energy from the vibrational motion. If, on the other hand, the output impedance of the system upstream of the channel is negative imaginary, vibrations of the channel walls can be excited. Experimental results agree with the predictions of the flow analysis for the simple vibrator. It is then argued that the respiratory system upstream of the larynx can be described as a tube 20 cm long in which the wave speed is reduced because of the distensibility of the bronchi, and which opens into the large reservoir of the lungs. Results of experiments in which the input impedance at the mouth was measured are consistent with this description. With this upstream impedance it is found that the simple vibrator would only be excited in a limited frequency range and would not allow many of the significant features of the vocal cord vibrations to be represented. Consequently a two‐degree‐of‐freedom model for the vocal cords is introduced. The flow analysis and impedance description are used in calculating the forces acting on the two‐mass model. It is predicted from the model that vibrations of the vocal vords are self excited over a range of frequencies. The properties of the self‐excited oscillations described by the model agree with the observed properties of the self‐excited vibrations in an experiment using a rubber membrane to represent the vocal cord, and are also consistent with several properties of the voice.

Glottal‐area time function and subglottal‐pressure variation

Yasuo Koike and Minoru Hirano

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1618-1627 (1973); (10 pages) | Cited 4 times

Online Publication Date: 12 Aug 2005

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High‐speed photography of the vibrating laryngeal structures was done on one female subject simultaneously with a direct recording of the vibratory air‐pressure variation in the trachea. The glottal dimensions and pressure data were obtained from this film using a semiautomated digital‐reduction technique. It was observed that the peaks of the subglottal‐pressure waves correspond with the dips in the glottal‐area waves, and also that the fundamental periodicity of the subglottal‐pressure wave represents the glottal‐area periodicity with good accuracy. Relations between the glottal‐area function and the glottal‐width function were considered. It is suggested that the glottal‐width function may be considered to be an approximate estimate of the glottal‐area function if the vibrating structure in the larynx is unaffected by pathology.

Ultrasound Axicon: a device for focusing over a large depth

C. B. Burckhardt, H. Hoffmann, and P.‐A. Grandchamp

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1628-1630 (1973); (3 pages) | Cited 2 times

Online Publication Date: 12 Aug 2005

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The B‐scan technique, which is used in ultrasonic medical diagnosis and in materials testing, suffers from a low lateral resolution because of the large diameter of the ultrasound beam. The present paper describes a beamforming device which focuses the beam over a large depth, i.e., the well‐known depth of focus problem is circumvented. An experimental device is described which gives a lateral resolution of 2 to 3 mm at a frequency of 2 MHz (λ = 0.75 mm in water).

Vibrational relaxation in multiple mixtures of two‐state gases

E. A. Dean

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1631-1634 (1973); (4 pages)

Online Publication Date: 12 Aug 2005

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The elements of a symmetrical matrix for the eigenvalue problem for vibrational relaxation times in a mixture of n two‐state gases are given. These elements depend upon the reaction rates for the various transitions and upon the mole fractions of the gases. Calculations for the three‐gas mixture O2/H2O/D2O are compared with experimental results for these mixtures. The large effect of a 50% D2O/H2O impurity on the relaxation time of O2 is attributed to a three‐step energy‐exchange chain: the near‐resonant V V transfer of vibrational energy from O2 to H2O, then a rapid exchange of vibration between H2O and D2O, followed by the de‐excitation of D2O by O2, which is an order of magnitude faster than the de‐excitation of H2O by O2.

Determination of the signs of the ratios of strain‐optical constants measured ultrasonically

Howard E. Pettersen and T. S. Narasimhamurty

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1635-1638 (1973); (4 pages)

Online Publication Date: 12 Aug 2005

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It is shown that a single light intensity measurement does not allow the determination of the sign of the ratio of strain‐optical constants determined ultrasonically. However, if an experiment is performed in which the ratios are overdetermined, it is possible to determine the signs by applying the criterion that the results of the various measurements must be consistent. The equations which must be satisfied for the criterion of consistency are obtained for nine of the 32 crystal classes. The application of the technique is presented with numerical values for the case of NaCl.

Ultrasonic absorption measurements in oriented benzene crystals

A. E. Victor and R. T. Beyer

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1639-1650 (1973); (12 pages)

Online Publication Date: 12 Aug 2005

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The ultrasonic absorption coefficient has been measured in single benzene crystals along the principal crystallographic axis. The range 6–38 MHz and at temperatures between 170° and 250°K. All three cases indicated a relaxation frequency near the middle of the frequency range (different in each case), and the values along the a‐ and c‐axes suggest the presence of other relaxation frequencies. The measurements have been compared in detail with the theories of Liebermann and Danielmeyer, but the agreement is far from satisfactory.

Rayleigh‐type surface wave on a linear viscoelastic half‐space

Roger D. Borcherdt

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1651-1653 (1973); (3 pages)

Online Publication Date: 12 Aug 2005

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The analytic solution for a Rayleigh‐type surface wave on a linear viscoelastic half‐space is obtained. The general viscoelastic solution predicts several properties of the surface wave distinct from those predicted by elasticity. The velocity, absorption coefficient, and displacement field are described theoretically.

Acoustic propagation in ducts with varying cross sections

Ali Hasan Nayfeh and Demetri P. Telionis

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1654-1661 (1973); (8 pages) | Cited 4 times

Online Publication Date: 12 Aug 2005

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The method of multiple scales is used to derive the equations that describe the spatial and temporal variation of the amplitudes and phases of a wave packet propagating in slowly varying hard‐walled or lined ducts. The analysis is carried out for rectangular as well as circular ducts. These equations are statements of the conservation of energy. For large admittance or high‐frequency modes, an approximate expression is obtained for the attenuation. This expression shows that all possible acoustic modes are attenuating. The results also show that decreasing the cross‐sectional area can lead to elimination of some of the acoustic modes.

Formal solution of the surface Helmholtz integral equation at a nondegenerate characteristic frequency

Peter H. Rogers

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1662-1666 (1973); (5 pages) | Cited 1 time

Online Publication Date: 12 Aug 2005

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The surface Helmholtz integral equation (SHIE) for the acoustic pressure on an object whose surface S vibrates harmonically with a given normal velocity, is known to fail by nonuniqueness at certain “characteristic” frequencies. These frequencies are identical to the eigenfrequencies of the homogeneous Dirichlet problem for a volume of fluid enclosed by the surface S. This paper deals with nondegenerate characteristic frequencies, that is, frequencies at which exactly one independent solution of the interior homogeneous Dirichlet problem exists but no nontrivial solutions of the interior homogeneous Neuman problem exist. The problem is reformulated in terms of operators on the Hilbert space of functions which are square integrable over S. The eigenvectors of the (skew‐Hermitian) Green's function operator for the interior Neumann problem provide an orthonormal basis for the space and, hence, the unknown Green's function operator for the exterior Dirichlet problem can be completely specified by its matrix elements with respect to these eigenvectors. The nonuniqueness failure of the SHIE is found to result from the indeterminacy of a single element of this infinite matrix. An expression for the indeterminate matrix element is obtained directly from the SHIE by a perturbation technique yielding a formal solution of the problem.

Generalized radiation impedances and reflection coefficients of circular and annular ducts

William E. Zorumski

J. Acoust. Soc. Am. Volume 54, Issue 6, pp. 1667-1673 (1973); (7 pages) | Cited 11 times

Online Publication Date: 12 Aug 2005

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Morse's equation for the radiation impedance of a vibrating rigid piston is extended to give the generalized radiation impedances Zmnl of all modes in circular and annular ducts which have arbitrary wall admittance β and which terminate in an infinite baffle. The equation for Zmnl is reduced to a single infinite integral which is a function of the mode radiation directivity factors. An infinite matrix equation is derived which relates the generalized mode reflection coefficients Rmnl to the radiation impedances. Results are presented which show that the duct‐wall admittance is a significant parameter in the effect of duct‐termination reflections and that mode‐coupling reflection effects may be more important than direct‐mode reflection effects.
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