bluuebunny/crossref_metadata_2025 huggingface dataset:
An excitation-pattern algorithm for the estimation of (2f1−f2) and (f2−f1) cancellation level and phase
Authors: Humes Larry E.
Published: October 2005

An excitation-pattern algorithm is described which provides an estimate of cancellation level and phase for the (2f1−f2) and (f2−f1) distortion products. An experiment is first conducted to demonstrate the need for such an algorithm for (f2−f1) level predictions. The results of this experiment, which employed three pairs of primaries having complementary input levels (L1=65, L2=85 dB; L1=85, L2=65 dB), do not agree with the predictions of another similar algorithm [E. Zwicker, J. Acoust. Soc. Am. 69, 1410–1413 (1981)]. A new excitation-pattern algorithm is then described. The predicted level behavior for (f2−f1) and (2f1−f2) is more accurate for the proposed algorithm. In addition, an accurate phase estimate is also provided by the new algorithm.
Effects of normal and pathologic eardrum impedance on sound pressure in the aided ear canal: A computer simulation
Authors: Egolf David P. , Feth Lawrence L. , Cooper William A. , Franks John R.
Published: October 2005

Reported herein are results of computer simulations of aided sound spectra in ears with normal and pathologic eardrum impedance. The computer technique used in this study has been reported elsewhere [D. P. Egolf, D. R. Tree, and L. L. Feth, J. Acoust. Soc. Am. 63, 264–271 (1978)]. Consequently, to develop reader confidence in the computer scheme, its application to real ears was first tested. This was accomplished by (1) comparing computed spectral data with in-the-ear measurements and (2) comparing real ear minus 2-cc coupler data—both computer generated—with an idealized difference curve published elsewhere [R. M. Sachs and M. D. Burkhard, unpublished rep. no. 20022-1, Industrial Research Products, Inc., Elk Grove Village, IL (1972)]. Results indicate that the wide variation in eardrum impedance among normals evidenced in other studies produces a corresponding wide variation in aided spectrum shape. Likewise, simulations utilizing two sets of pathologic eardrum impedance data obtained from the literature show that aided sound spectra in such ears are likely to be significantly different from those occurring in normal ears. These findings suggest, as others have concluded, that there may be a substantial variation in spectrum shape among individuals wearing identically the same hearing aid—even if those individuals have normal hearing. In conclusion, questions are raised about the use of real-ear simulators and the need for a comprehensive computer-based model of an entire hearing aid.
High-synchrony cochlear compound action potentials evoked by rising frequency-swept tone bursts
Authors: Shore Susan E. , Nuttall Alfred L.
Published: October 2005

The auditory compound action potential (CAP) represents synchronous VIIIth nerve activity. Clicks or impulses have been used in the past to produce this synchrony under the assumption that the wide spectral spread inherent in transient signals will activate a large portion of the cochlear partition. However, the observation that only auditory nerve units tuned above 3 kHz contribute to synchronous activity in the N1P1 complex of the CAP [Dolan et al., J. Acoust. Soc. Am. 73, 580–591 (1983)] suggests that temporal delays imposed by the traveling wave result in an asynchronous pattern of VIIIth nerve activation. In order to determine if units tuned below 3 kHz could be recruited into the CAP response, the present study uses tone bursts of exponentially rising frequency to hypothetically activate synchronous discharges of VIIIth nerve fibers along the length of the cochlear partition. The equations defining the frequency sweeps are calculated to be the inverse of the delay-line characteristics of the guinea pig cochlear partition.

The resultant sweeps theoretically cause a constant phase displacement of a large portion of the cochlear partition at one time. Compound action potentials recorded in response to the rising frequency sweeps were compared to CAPs evoked by corresponding falling frequency sweeps and clicks. Analysis of the CAP waveforms showed narrower N1 widths and larger N1 and P1 amplitudes for rising sweeps when compared to falling sweeps. This is consistent with the hypothesis of increased synchrony. A further test of the hypothesis was made by using high-pass masking noise to evaluate the contributions of discrete cochlear locations to the CAP (‘‘derived’’ CAP). Latency functions of the derived CAPs for clicks and falling frequency sweeps showed progressive increases in latency as the cutoff frequency of the high-pass filter was lowered. The latency of the derived CAP for these stimulus conditions reflects traveling wave delays [Aran and Cazals, ‘‘Electrocochleography: Animal studies,’’ in Evoked Electrical Activity in The Auditory Nervous System (Academic, New York, 1978)]. In contrast, derived CAPs obtained from rising sweeps showed no change in latency for any cutoff frequencies, indicating a constant delay of response for fibers with different characteristic frequencies (CFs). These results support the theoretical premise underlying the derivation of the rising sweep: Spectral energy with the appropriate temporal organization, dictated by basilar membrane traveling wave properties, will increase CAP synchrony.
Sound intensity processing by the goldfish
Authors: Fay Richard R.
Published: October 2005

Capacities of the goldfish for intensity discrimination were studied using classical respiratory conditioning and a staircase psychophysical procedure. Physiological studies on single saccular (auditory) nerve fibers under similar stimulus conditions helped characterize the dimensions of neural activity used in intensity discrimination. Incremental intensity difference limens (IDLs in dB) for 160-ms increments in continuous noise, 500-ms noise bursts, and 500-ms, 800-Hz tone bursts are 2 to 3 dB, are independent of overall level, and vary with signal duration according to a power function with a slope averaging −0.33. Noise decrements are relatively poorly detected and the silent gap detection threshold is about 35 ms. The IDLs for increments and decrements in an 800-Hz continuous tone are about 0.13 dB, are independent of duration, and are level dependent. Unlike mammalian auditory nerve fibers, some goldfish saccular fibers show variation in recovery time to tonal increments and decrements, and adaptation to a zero rate. Unit responses to tone increments and decrements show rate effects generally in accord with previous observations on intracellular epsp’s in goldfish saccular fibers. Neurophysiological correlates of psychophysical intensity discrimination data suggest the following: (1) noise gap detection may be based on spike rate increments which follow gap offset; (2) detection of increments and decrements in continuous tones may be determined by steep low-pass filtering in peripheral neural channels which enhance the effects of spectral ‘‘splatter’’ toward the lower frequencies; (3) IDLs for pulsed signals of different duration can be predicted from the slopes of rate–intensity functions and spike rate variability in individual auditory nerve fibers; and (4) at different sound pressure levels, different populations of peripheral fibers provide the information used in intensity discrimination.
Acoustic propagation over an impedance plane
Authors: Nobile Matthew A. , Hayek Sabih I.
Published: October 2005

A new solution is obtained for the acoustic pressure field generated by a point source and scattered by a locally reacting impedance covered plane. The new solution is obtained in the form of an asymptotic series which has been shown to agree well with other studies. One of the most important features of this solution is that higher-order terms can be calculated from preceding terms in the series by the use of recursion formulas. Comparing data predicted from this solution with that from a numerical integration of the exact expression shows the asymptotic series to be extremely accurate, even for relatively low values of the parameter kR. Not surprisingly, the plane-wave solution often shows major deviations from the exact integral solution.
A general normal mode solution for the free vibration of the rectangular parallelepiped
Authors: Hill Eric v. K.
Published: October 2005

A general normal mode solution is presented for the free vibration of the rectangular parallelepiped with arbitrary, static boundary conditions and body forces. This is followed by three examples of the solution procedure. Dynamic body forces and boundary conditions are also mentioned.
Stability of the Rijke thermoacoustic oscillation
Authors: Kwon Young-Pil , Lee Byung-Ho
Published: October 2005

The stability limit of the Rijke oscillation induced from heated wires in a tube with air current is investigated on the basis of the analysis of heat transfer. By developing a general formulation for the thermoacoustic power generation, it is shown that the in-phase component of the fluctuating heat release from a heater with the acoustic pressure can generate the acoustic power. The heat transfer response of an isothermal wire to the particle velocity of an acoustic wave is analyzed numerically by treating the flow as incompressible and two dimensional. The amplitude and phase of the fluctuating heat release are computed and displayed in graphs for various values of the air current velocity and the wire radius normalized by the angular frequency and the thermal diffusivity. The acoustic power generation from a heater wire is expressed in terms of an efficiency factor. It is found that the power generation can be maximized if both the normalized velocity of the air current and the normalized radius of the wire become around unity. By equating the acoustic power generation to the power dissipation in the tube, the limiting condition for the onset of oscillation is obtained for the steady heat input. The theoretical prediction to the stability limit is compared with available experimental data and the good agreement demonstrates a substantial verification of the present analysis.
The anatomical consequences of acoustic injury: A review and tutorial
Authors: Saunders James C. , Dear Steven P. , Schneider Mark E.
Published: October 2005

The anatomic consequences of acoustic overstimulation are explored in this presentation, and attention is directed toward issues where improvements in technology and empirical observation are needed before further advances in our understanding can be achieved. Gains have been made in the last decade in appreciating sound-induced cochlear injury, but there is now a need to evaluate not only cochlear pathology but also the functional state of the surviving structures. There is a wealth of information about the susceptibility of inner or outer hair cells to acoustic injury; however, the etiology of this injury is not yet fully understood. In addition, current ideas concerning the effects of noise on hair-cell stereocilia, hair-cell synapses, the cochlear vascular supply, and the central auditory pathways are in a state of flux and are either undergoing revision or emerging. Other issues, such as the basis of temporary or permanent threshold shift at the cellular level, and the individual differences in susceptibility to injury are in need of a fresh approach. It would seem that the time is now ripe to review our knowledge, recognize its gaps, and develop testable hypotheses concerning the mechanisms of acoustic injury to the ear.
Speech recognition in noise by individuals with mild hearing impairments
Authors: Suter Alice H.
Published: October 2005

The study was designed to test the validity of the American Academy of Ophthalmology and Otolaryngology’s (AAOO) 26-dB average hearing threshold level at 500, 1000, and 2000 Hz as a predictor of hearing handicap. To investigate this criterion the performance of a normal-hearing group was compared with that of two groups, categorized according to the AAOO [Trans. Am. Acad. Ophthal. Otolaryng. 63, 236–238 (1959)] guidelines as having no handicap. The latter groups, however, had significant hearing losses in the frequencies above 2000 Hz. Mean hearing threshold levels for 3000, 4000, and 6000 Hz were 54 dB for group II and 63 dB for group III. Two kinds of speech stimuli were presented at an A-weighted sound level of 60 dB in quiet and in three different levels of noise. The resulting speech recognition scores were significantly lower for the hearing-impaired groups than for the normal-hearing group on both kinds of speech materials and in all three noise conditions. Mean scores for group III were significantly lower than those of the normal-hearing group, even in the quiet condition. Speech recognition scores showed significantly better correlation with hearing levels for frequency combinations including frequencies above 2000 Hz than for the 500-, 1000-, and 2000-Hz combination. On the basis of these results the author recommends that the 26-dB fence should be somewhat lower, and that frequencies above 2000 Hz should be included in any scheme for evaluating hearing handicap.
Prior stimulation and the masking-level difference
Authors: Yost William A.
Published: October 2005

Signal detection in diotic (NoSo) and dichotic (NoSπ) conditions was measured as a function of the stimulus parameters of the noise that preceded the signal-plus-masker. When the signal and masker were both pulsed, dichotic signal detection was worse than when the masker was continuous or when the onset of the masker preceded the signal-plus-masker by at least 500 ms. The dichotic detection thresholds decreased as the duration of the pulsed signal plus pulsed masker was increased. The level, spectrum, interaural configuration, duration, and temporal proximity of the prior noise (forward fringe) relative to the masker and/or signal and masker were all investigated. Almost any difference between the parameters of the fringe and the masker resulted in poorer signal detection in the dichotic conditions. These same stimulus conditions produced small (less than 2.2 dB) changes in the diotic detection thresholds. The various models of the Masking-Level Difference (MLD) may be modified to qualitatively describe some of these results.
The comparative effects of signal sensation level and sound-pressure level on interaural time discrimination
Authors: Cohen Marion F. , Koehnke Janet , McClave Anne E. , Pallanck Patricia Gregorio
Published: October 2005

A series of experiments was performed to examine the extent to which precision of interaural time discrimination depends on the sound-pressure level (SPL) and/or sensation level (SL) of the signal. All experiments used a tone burst signal and a continuous white noise masker, which was either diotic or interaurally phase reversed. Results of the first experiment indicate that (1) at equal signal SLs, interaural time and intensity discrimination is more precise when measured with the added diotic noise, and (2) addition of the phase reversed noise, previously shown to cause less precise interaural time discrimination, has a similar effect on interaural intensity discrimination. In the second experiment, interaural time JNDs for a signal of constant SPL were measured as a function of noise level. Results show that a low-level diotic noise can benefit interaural time discrimination, particularly at 500 Hz. The third and fourth experiments were performed to measure interaural time discrimination as a function of increasing signal SPL but constant signal-to-noise ratio. The data show the JND decreasing with increasing signal SPL at nearly the same rate with or without the added noise, indicating that an increase in signal-to-noise ratio is not necessary for improved discrimination.
Acoustic vibration of the amphibian eardrum studied by white noise analysis and holographic interferometry
Authors: Anson M. , Pinder A. C. , Keating M. J. , Chung S. H.
Published: October 2005

The motion of the amphibian eardrum under free-field acoustic stimulation was investigated using time-averaged holography. We show that the amplitude is linearly related to sound pressure up to ±1000 nm. The frequency response of the eardrum shows broad resonance characteristics with a main peak between 1200–2200 Hz. The velocity of the tympanic membrane’s motion at its resonance frequency matches the acoustic velocity of air particles. The resonance characteristics of the eardrum are also revealed by white noise stimulation. The power spectrum obtained by Fourier transformation of the autocorrelation of the response to noise resembles closely that obtained by holography.
Effect of sound-absorptive facings on the sound transmission through panels
Authors: Trochidis A.
Published: October 2005

The effect of sound-absorptive facings on the airborne-sound transmission of panels is discussed. The response of a simple model, consisting of an infinite elastic plate with an attached sound-absorptive facing, to acoustical excitation is calculated. Numerical calculations of the transmission loss, carried out for typical examples, show the influence of the main parameters involved.
Classification of soils based on acoustic impedance, air flow resistivity, and other physical soil parameters
Authors: Martens M. J. M. , van der Heijden L. A. M. , Walthaus H. H. J. , van Rens W. J. J. M.
Published: October 2005

Measurements are presented that can be used to test theories that predict acoustical characteristics of outdoor surfaces. The specific acoustic impedances of forest soils, grass-covered surfaces, and bare sandy soils have been measured in situ using an inclined track method. Best-fit effective flow resistivities have also been deduced from the acoustical measurements. For grass-covered and forest soils the soil stratification has been determined and measurements have been carried out to determine the acoustical significance of the different layers. Physical soil parameters have also been measured, including porosity; water, air, and solid matter content; soil texture; and directly measured air flow resistivity. It is found possible to classify investigated soils as acoustically soft, moderate, or hard, both according to the behavior of the reflection coefficient and impedance with frequency and to the corresponding best-fit values of effective flow resistivities. Bare sandy soils are found to be acoustically hard surfaces. Forest soils may be classified, in most cases, as acoustically soft. For grass-covered and forest soils, the real part of the acoustic impedance is relatively independent of frequency, while the imaginary part strongly decreases with frequency. Litter layers do not influence acoustical soil properties. The important role for humus and root layers that has been suggested is not always confirmed by air flow resistivity measurements reported in this paper. A classification of soils based on measured air flow resistivity is possible but is only roughly in agreement with the acoustical classification. Predictions of acoustic impedances, based on the equations of Delany and Bazley [Appl. Acoust. 3, 106–116 (1970)] and on directly measured flow resistivities, are not always satisfactory. The predictions are particularly poor for forest floors.
Normal mode cycle distance and beam displacement, time delay, etc., for low (non-WKB) frequencies
Authors: Koch Robert A. , Lindberg Jo B.
Published: October 2005

Koch et al.’s [J. Acoust Soc. Am. 73, 1567–1570 (1983)] formulation of the impedance boundary condition normal mode identification algorithm is used to develop the relationship between the normal mode and geometric ray quantities for low frequency, where previous analyses, employing WKB or other high-frequency approximations, may not be valid. The result shows that mode normalization is not uniquely related a priori to a mathematically meaningful horizontal wavenumber derivative of mode number. Instead, some auxiliary conditions must be invoked to uniquely define cycle distance as a single mode quantity (as opposed to the range periodicity of interference between two modes) given by a mode number derivative and corresponding in appropriate limits to the geometric ray cycle distance. A suggestion for constructing from this result an optimal eigenvalue predictor for numerical eigenmode calculations is discussed.
Passive acoustic location of bowhead whales in a population census off Point Barrow, Alaska
Authors: Cummings W. C. , Holliday D. V.
Published: October 2005

A sonobuoy array placed in the nearshore lead was used for locating bowhead whale sounds to determine if whales migrated past census stations beyond visual range and were uncounted. Based on a sample of 182 whale sounds (over 48 h) from closest point of approach (CPA) distances out to more than 10 km, 68% originated beyond 2 km (CPA), where only 1% of the 242 whales were sighted. No whales were sighted beyond 3 km during this time, but 53% of the located sounds originated that far and beyond. Thirty-seven other bowhead sounds over 15 h were distributed out to 6 km. Two tracked whales moved at average speeds of 1.5 and 1.8 kn. Maximum location error was 1%–25% in a sector of 120° × 5–10 km, depending upon bearing and range. Most whale sounds were low-frequency moans, trumpeting roars, and repetitive sequences (songs) with peak spectrum source level up to 189 dB re: 1 μPa, 1 m. Lack of correlations between numbers of sounds and sighted whales precluded using bowhead sounds to count individuals or even to extrapolate ratios of unseen to observed whales.
Normal mode measurements and remote sensing of sea-bottom sound velocity and attenuation in shallow water
Authors: Zhou Ji-xun
Published: October 2005

The dispersion analysis of explosive signals and measurements of individual mode attenuation in the Yellow Sea is reported. By adjusting input parameters of a normal mode computer program and making the calculated results coincide with field data, the compressional wave velocity and attenuation in the sediment for the frequency range of 80–800 Hz is simultaneously deduced. The sea-bottom velocity, attenuation, and its frequency dependence, probed from two sea areas with a different depth and sound velocity profile in the summer and the winter, are very close. Resultant sea-bottom attenuation approaches the results of earlier workers at the upper end of the frequency band and joins with the data obtained by others at the lower end, and the absorption appears to have a nonlinear frequency dependence (α=0.37 f1.84 dB/m kHz). The errors due to the change of environmental parameters (such as water depth, water sound velocity profile, sediment density, and seafloor roughness) are discussed.
Water-borne sound insertion loss of a planar compliant-tube array
Authors: Junger M. C.
Published: October 2005

This lumped-parameter analysis models the compliant-tube array as a homogeneous fluid layer, thin in terms of wavelengths, whose bulk modulus and thickness match those of the tube array. For closely packed arrays, the results are in good agreement with those of the rigorous, numerical solution. For sparse arrays, the lumped-parameter model fails near and above the fundamental tube resonance frequency because it does not account for accession to inertia.
Exponential substitution for Kirchhoff scattering from Gaussian rough surfaces
Authors: Berman David H. , Perkins John S.
Published: October 2005

In order to perform calculations which require many evaluations of surface-scattering cross sections, an approximation has been developed for integrals appearing in the Kirchhoff theory of rough surface scattering. This approximation replaces a two-dimensional integral evaluation by a simple function evaluation. In the radially symmetric case, evaluation of Kirchhoff cross sections is speeded by a factor of about 20. The basis of the approximation, called exponential substitution, is to fit Kirchhoff integrals by a two-parameter scaled spectrum of surface heights. M. V. Berry [J. Phys. A: Gen. Phys. 8, 566–684 (1975)] chose parameters to fit zeroth and second moments of Kirchhoff integrals whereas for this study parameters were chosen to fit the zeroth moment and peak values of the integrals. Numerical results are presented which show that the present version of exponential substitution is more accurate than previous versions in describing scattering near the forward direction. PACS numbers: 43.28.Fp
Multidimensional Born velocity inversion: Single wideband point source
Authors: Esmersoy Cengiz , Oristaglio Michael L. , Levy Bernard C.
Published: October 2005

The inverse scattering problem for an acoustic medium is considered within the approximate direct inversion framework. As opposed to iterative methods, the direct inversion approach gives an estimate of the medium velocities by operating on the observed scattered field without repeated solutions of the forward problem. Previous solutions to the multidimensional Born velocity inversion problem require either coincident source and receiver arrays or plane-wave sources. In both cases an array of point sources is required to collect the proper data for inversion. In this paper, the solution to the single point source problem is derived. It is shown that by extrapolating and imaging the observed scattered field appropriately, the projections of the velocity function at all angles can be obtained. The velocities are, then, reconstructed by the inverse Radon transform method of tomography.
Further studies of the scattering of a Gaussian beam from a fluid–solid interface
Authors: Harris John G. , Pott John
Published: October 2005

Our earlier study [J. Pott and J. G. Harris, J. Acoust. Soc. Am. 76, 1829–1838 (1984)] of the reflection and refraction, at a plane fluid–solid interface, of a Gaussian beam is continued. When the angle of incidence approaches the angle at which the compressional wave is critically refracted, a lateral wave is excited both in the fluid and in the solid. In the fluid, this wave interferes with the reflected beam, making it appear shifted and distorted. A second lateral wave is excited in the fluid when the angle of incidence nears that at which the shear wave is critically refracted. However, this angle is usually quite close to the Rayleigh angle. Thus the nearly coincident excitation of a leaky Rayleigh wave (examined in our earlier paper) masks any effect the lateral wave has. But even for angles of incidence not near these three critical angles, the axis of the reflected beam is slightly rotated and displaced. The refracted beams (examined in our earlier paper) spread quite rapidly in the solid, but, by using a thin lens to focus the incident beam, this spreading can be reduced somewhat.
Mean-field renormalization and rough surface reflection of acoustic waves
Authors: Hill N. R. , Lerche I.
Published: October 2005

It is shown that the technique of mean-field renormalization permits solution of the problem of perfect reflection from a rough surface. The results for both the statistically sharp reflected wave (the mean wave) and the fluctuations around the mean wave are precise provided that the rms height of the rough surface is small compared to the incident wavelength. In particular, the results are valid for any arbitrary ratio of the spatial scale of the roughness variations compared to the incident wavelength. It is shown that power is conserved to the order considered and that certain basic integrals do not depend for their convergence on the vanishing of the surface height autocorrelation function at large lags. As a consequence, a sinusoidally varying surface can be treated as a limiting case using the mean-field renormalization approach.
Diffraction of acoustic plane waves: A time-domain analysis
Authors: Lasota Henryk
Published: October 2005

A time-domain approach to some fundamental problems of plane-wave diffraction and radiation is developed for the three classical cases of boundary conditions. The usual, short-wave approximation of the Kirchhoff integral has been avoided, and the general solutions obtained are valid for the whole field. The contributions of the simple and double sources (monopoles and dipoles) distributed on the wave front are regarded separately, this analysis enabling a closer look to be taken at the plane-wave forward-only propagation mechanisms. A uniformly excited plane radiates a ‘‘pure’’ plane wave, and the presence of any nonuniformity in the impulsive excitation gives rise to an additional aperture-induced wave that depends upon actual boundary conditions. The result emphasizes the Young–Rubinowicz interpretation of diffraction phenomena, the edge wave being a special case of the aperture wave.
Propagation of bounded ultrasonic beams in anisotropic media
Authors: Vezzetti David J.
Published: October 2005

A method of computing the elastic displacement and stress in an anisotropic elastic medium (crystal) when the medium is excited at its surface by a given displacement or stress is developed. In particular, it is shown how arbitrary boundary conditions generally induce both diagonal and off-diagonal stresses and longitudinal, as well as transverse, displacements. A number of special cases which can be handled analytically are discussed in detail, and a perturbation theory for narrow angle beams is developed. Comparisons are made with previous works which considered propagation of plane waves in nonpure mode directions.
Critique of ‘‘Measures of the sentence intonation of read and spontaneous speech in American English’’ [J. Acoust. Soc. Am. 7
7, 649–657 (1985)]
Authors: Repp Bruno H.
Published: October 2005

The article by Lieberman et al. [J. Acoust. Soc. Am. 77, 649–657 (1985)] was judged unsuitable for publication by three independent reviewers and this associate editor. This letter documents the main criticisms on which that judgment was based.
Reply to Bruno H. Repp
Authors: Lieberman Philip , Katz William , Jongman Allard , Zimmerman Roger , Miller Mark
Published: October 2005

The reader will readily note that much of Repp’s criticism [J. Acoust. Soc. Am. 78, 1114–1116 (1985)] reflects his contention that there has been a procedural transgression on the part of the authors and the Society that establishes a ‘‘dangerous precedent.’’ Since Repp provides a partial account we feel that it is first necessary to address this issue.
Plosive consonant identification in ambiguous sentences
Authors: Pols L. C. W. , Schouten M. E. H.
Published: October 2005

The hypothesis tested in this paper is that the acoustic–phonetic information at the sentence level (irrespective of the meaning of the sentence) makes it easier to interpret those cues to plosive consonant identity which are contained in vocalic transitions. Listeners were given a two-way choice in meaningful Dutch sentences which allowed two different intervocalic plosive consonants in the same position, and from which various parts of the VCV segments (plosive burst, vocalic transitions) had been deleted. The results were compared with results from a condition in which the VCV segments were presented without the sentence context. The hypothesis was confirmed for CV transitions, except for /k/, but disconfirmed for nearly all VC transitions. This could mean that in experiments involving the perception of isolated VCV or CVC utterances, whether spoken in isolation or excised from longer utterances, the contribution of the CV transition to plosive consonant perception may be underestimated.
Response of a compliant slab to inviscid incompressible fluid flow
Authors: Evrensel Cahit A. , Kalnins Arturs
Published: October 2005

The dynamics of harmonic wave trains on the interface between a compliant slab and the flow of an inviscid fluid is explored theoretically. The slab is treated as an infinite, elastic or viscoelastic solid of finite thickness, bonded to a rigid half-space. The viscoelastic behavior is modeled by an isotropic Voigt constitutive model. The two media are coupled through stress and velocity, normal to the surface of the slab. The proposed mathematical model is used to predict the appearance of unstable surface waves of the coating.
Nonlinear effects in the coupled response of tiles bonded to a plate
Authors: El-Raheb Michael , Wagner Paul
Published: October 2005

The coupled response to a large impulse on tiles bonded to a finite plate is studied. The analysis includes geometric nonlinearity born from boundary restraint in the plane, which stiffens the plate transversely. It also includes material nonlinearities born from plasticity of the plate’s material and from properties of a polymer bond including memory and dissipation. The equations of motion are solved by the Galerkin method using linearized eigenfunctions of the system as trial functions. A strip of plate which is one tile wide is modeled.
Comments on: ‘‘PERUSE: A numerical treatment of rough surface scattering for the parabolic wave equation’’ [J. Acoust. Soc. Am. 7
5, 1415–1432 (1984)]
Authors: Laura P. A. A.
Published: October 2005

The fact that this important and very timely contribution is based on the use of a sequence of conformal mappings has motivated the writer to prepare a brief survey of modern applications of conformal mappings which may be of interest to other researchers in the acoustics and vibrations field.
Hot-film anemometry measurement of hydroacoustic particle motion
Authors: Dubbelday Pieter S.
Published: October 2005

Hydroacoustic particle motion may be detected by hot-film anemometry. Free convection causes a vertical flow that acts as a bias for vertical particle motion, resulting in a linear dependence of output voltage on the displacement. For horizontal particle motion, the output frequency is twice that of the acoustic field, and the output depends quadratically on the motion. An imposed bias flow increases the sensitivity and provides independence of the direction of gravity. The measurements are performed for water and ethylene glycol with sensors of diameters 25, 50, and 150 μm and temperature differences between sensor and medium of 15°, 30°, and 45 °C. The frequency range for horizontal motion is 20–160 Hz and for vertical motion is 20–500 Hz. The results are presented in terms of dependence of the ac Nusselt number as a function of relative displacement, Fourier number, and Rayleigh or Grashof number. At constant intensity, the output is inversely proportional to frequency to the 3/2 power for the horizontal case, and inversely proportional to the frequency for the vertical case.
The response of a semi-infinite fiber to a pulse applied asymmetrically to its end
Authors: Wilson Lynn O.
Published: October 2005

McKenna and Simpkins [J. Acoust. Soc. Am. 78, 1675–1683 (1985)] have developed a normal mode theory concerning wave propagation down a semi-infinite or finite elastic cylinder due to a time-dependent load applied at one or both ends. To test the practicality of applying this theory, a nontrivial model problem concerning the dynamic response of a glass fiber to a certain pulse applied at its end representing tensile fracture is studied. After considerable analytical effort, the expansion coefficients for the modes are computed. Calculations concerning displacements and strains of the dominant modes are presented. When necessary, additional asymptotic analyses are done. It is possible to obtain a comprehensive description of the fiber’s response to the pulse. However, the effort required to apply the theory to a general problem is extensive. If the problem formulation admits considerable simplification of the expressions for the modal expansion coefficients, the theory is probably both elegant and meaningful.
An analysis of doubly rotated quartz resonators utilizing essentially thickness modes with transverse variation
Authors: Stevens D. S. , Tiersten H. F.
Published: October 2005

Closed-form asymptotic expressions for the frequency–wavenumber dispersion relations in doubly rotated quartz plates vibrating in the vicinity of the odd pure thickness frequencies are derived from the equations of linear piezoelectricity and the associated boundary conditions on the major surfaces. The usual assumptions of small piezoelectric coupling and small wavenumbers along the plate are made and it is supposed that the pure thickness frequencies are sufficiently different that one pure thickness wave is dominant at a time. In the treatment the mechanical displacement is decomposed along the eigenvector triad of the pure thickness solution to facilitate the asymptotic analysis. The fact that the wavenumbers along the plate are restricted to be small significantly reduces the complexity of the equations without neglecting any transformed elastic constants. The resulting asymptotic dispersion equation enables the construction of a scalar differential equation describing the transverse behavior of essentially thickness modes of vibration in doubly rotated quartz plates. The scalar equation is applied in the analysis of both trapped energy resonators with rectangular electrodes and contoured crystal resonators using established procedures. In particular, calculations performed for the contoured SC cut and a number of other doubly rotated orientations are shown to be in excellent agreement with experiment. Since the differential equation for each harmonic family depends on the order of the harmonic and in the general doubly rotated case contains mixed derivatives in the plane of the plate, a different transformation is required for each harmonic family to obtain the coordinate system in which the mixed derivatives do not appear and, hence, the equation is separable. An interesting consequence of this transformation is that since the nodal planes of the anharmonics of each harmonic family of the contoured SC-cut quartz resonator are oriented along the transformed coordinate system for that harmonic family, they are oriented differently for each harmonic family.
Representation of system response using expansions of Hermite and Beranek functions
Authors: Lyon Richard H.
Published: October 2005

A new representation of system functions in the time and frequency domains using Hermite functions is introduced. The properties of such a representation are compared and contrasted with the well-known Laguerre expansion of system temporal response introduced by Y. W. Lee [Statistical Computation Theory (Wiley, New York, 1960), Chap. 19]. It is argued that the Hermite functions are more relevant representations of systems with many degrees of freedom, and offer other mathematical and conceptual advantages as well. A new set of functions related to Hermite functions by the Hilbert transform are introduced, and are named Beranek functions. The use of these representations is illustrated by an application to the transfer function for a lossy acoustical pipe.
What is ‘‘Synchrony suppression’’?
Authors: Greenwood Donald D.
Published: October 2005

Synchrony of discharge of auditory neurons to two-tone stimuli and ‘‘synchrony suppression’’ have been analyzed by examining the implications of the definition of vector strength. Synchrony suppression, defined as the reduction in the vector strength for one component when a second is introduced, occurs by definition when partial (‘‘half-wave’’) rectification occurs in an otherwise linear system. It does so with the usual shifts (on the abscissa) of empirical vector strength curves, disproving any necessity for compressive or other nonlinearities. Synchrony suppression, is sometimes defined incompatibly as the shift in dB of a vector strength curve—said to be the magnitude of suppression. That this conception is incorrect is shown by the identification of partial rectification with vector strength reduction and curve shift, but it can be shown to be a logical fallacy as well. The vector strength definition was also applied to the complex waveform obtained at the output of an instantaneous amplitude compressive nonlinearity. The shifts of vector strength growth and decay curves (at their crossover points) necessarily equal those in the linear case for any compressive nonlinearity that compresses equal inputs equally. But such a compressive nonlinearity is not without noticeable effects on vector strengths. If the input levels lie in the range leading to compressed outputs, differences in the relative input levels will be accentuated in the relative output levels in the period histogram. Compression thus contributes to greater differences in the vector strengths, for unequal input levels, than in the linear case. More visible effects on vector strength curves result from waveform distortion, which reduces vector strength saturation and crossover values and causes them to recede at higher input levels.
Compound action potential thresholds and tuning curves in the alligator lizard
Authors: Turner Robert G. , Shepard Neil T.
Published: October 2005

Compound action potential (AP) thresholds and tuning curves were measured in the alligator lizard using techniques similar to those used with the mammal. For tone burst stimuli, the AP was a major component of the gross response, the electrical response to sound recorded by a wire electrode near the cochlea. The AP thresholds agreed well with threshold estimates based on single-fiber data. A forward masking paradigm produced AP tuning curves which resemble single-fiber tuning curves. A simultaneous masking paradigm produced curves which match the boundaries of single-fiber two-tone rate suppression. The AP thresholds and tuning curves provide useful information about the peripheral physiology of the ear of the alligator lizard.
Acoustic response and tuning in saccular nerve fibers of the Goldfish (c
a
r
a
s
s
i
u
s a
u
r
a
t
u
s)
Authors: Fay Richard R. , Ream Timothy J.
Published: October 2005

The acoustic frequency selectivity of over 500 saccular nerve fibers of the goldfish was studied using automated threshold tracking based on spike rate increments defined statistically. Saccular fibers of the goldfish show great variation in (1) best sensitivity (−26 to +35 dB re: 1 dyn/cm2), (2) best frequency (below 100 to 1770 Hz), (3) spontaneous rate (0 to over 200 spikes/s), (4) spontaneous type (silent, regular, irregular, burst), and (5) degree of tuning (Q10 dB from <0.1 to 2). Saccular fibers may be grouped into four nonoverlapping categories based on tuning and best frequency: (1) untuned (less than 10-dB variation in sensitivity between 100 and 1000 Hz), (2) low frequency (BF from below 120 to 290 Hz), (3) midfrequency (BF between 330 and 670 Hz), and (4) high frequency (BF between 790 and 1770 Hz). Within each category, all spontaneous rates and types, and all degrees of tuning can be observed. The least sensitive fibers within each group have zero spontaneous rates. The goldfish is like all other vertebrates studied in that the peripheral auditory system is adapted for frequency selectivity throughout the animal’s entire frequency range of hearing. Peripheral tuning most likely accounts for behavioral determinations of the ‘‘auditory filter’’ and for the detectability of signals masked by noise. The signal-to-noise ratio enhancement provided by these peripheral filters is likely to be of primary biological significance. A ‘‘place principle’’ of sound quality analysis based on lines ‘‘labeled’’ according to best frequency in the brain cannot be ruled out on the basis of the peripheral physiology.
Discrimination of spectral density
Authors: Hartmann W. M. , McAdams Stephen , Gerzso Andrew , Boulez Pierre
Published: October 2005

Experiments were performed to determine the ability of human listeners to discriminate between a sound with a large number of spectral components in a band, of given characteristic frequency and bandwidth, and a sound with a smaller number of components in that band. A pseudorandom placement of the components within the band ensured that no two sounds were identical. The data suggested that discrimination is primarily based upon the perception of temporal fluctuations in the intensity of the sound and secondarily upon resolved structure in the spectrum, perceived as tone color. Experiments using clusters of complex harmonic sounds showed that listeners are able to use the information in upper harmonic bands to discriminate spectral density.
Effects of signal envelope on the pitch of short sinusoidal tones
Authors: Rossing Thomas D. , Houtsma Adrianus J. M.
Published: October 2005

The pitch of short sinusoidal tones with exponentially rising or decaying envelopes is judged higher than the pitch of a gated tone of the same frequency, duration, and energy. The upward pitch shift depends on the rise or decay rate, the intensity, and the frequency. The effect, which requires a nonlinearity in the auditory system, cannot be adequately explained by existing models of hearing. Control experiments on pitch matching for short tones of varying duration and varying intensity are described. These suggest that envelope-induced pitch effects are linked to changes in average intensity, so that they are essentially the same as intensity-induced pitch changes. A model based on these considerations is proposed.
Stimulus-based limitations on the discrimination between different temporal orders of tones
Authors: Kelly William J. , Watson Charles S.
Published: October 2005

Listeners’ abilities to discriminate the order of two tones, of frequency 500 Hz and 500 Hz+Δ f, separated by less than 5 ms, were measured in terms of threshold durations (T) for the tones. The experiment was repeated for values of Δ f  between 5 and 160 Hz. The relation of the duration threshold to Δ f was well-described by the reciprocity equation, Δ f T=K, for K=0.16. This reciprocity corresponds to a constant overlap of the main lobes of the power spectra for the tones of about 70%–80%. Addition of a trailing context tone severely degraded the ability to discriminate temporal order, increasing the value of the reciprocity constant to approximately K=1.8. The primary effect of the context tones was to increase the duration required for accurate discrimination, rather than to impair actual frequency resolution. Implications of these results for speech perception are discussed.
Lateralization of bands of noise and sinusoidally amplitude-modulated tones: Effects of spectral locus and bandwidth
Authors: Trahiotis Constantine , Bernstein Leslie R.
Published: October 2005

Lateralization of narrow bands of noise was investigated while varying interaural temporal disparity (ITD), center frequency, and bandwidth, utilizing an acoustic pointing task. Stimuli were narrow bands of noise centered at octave intervals between 500 Hz and 4 kHz with bandwidths ranging from 50–400 Hz. In a second experiment, lateralization for bands of noise and sinusoidally amplitude-modulated (SAM) tones, whose spectral content was constrained to be no lower than 3.8 kHz, was assessed. Overall, relatively large extents of laterality were obtained from all four listeners for ITDs of low-frequency bands of noise. Increasing the bandwidth of these noises did not yield consistent changes in the extent of laterality across ITDs and listeners. Most targets centered at high frequencies were lateralized near the midline. However, three of the four listeners did exhibit rather large displacements of the intracranial image when the bandwidth of the high-frequency noises was 400 Hz or greater. Interestingly, ITDs within high-frequency SAM tones were relatively ineffective. Thus, it appears that ITDs of relatively wide-band, high-frequency stimuli can mediate rather substantial extents of laterality. However, these effects are highly listener-dependent.