bluuebunny/crossref_metadata_2025 huggingface dataset:
Optical holography for the study of sound radiation from vibrating surfaces
Authors: Hansen Colin H. , Bies David Alan
Published: October 2005

Time-averaged holography has been used to quantitatively investigate sound radiation from an edge-clamped circular flat plate mounted in an infinite rigid baffle. For a particular mode of vibration, the plate response is measured using holography and the sound power radiated is measured in a reverberant room with the plate mounted in one of the room walls. From these measurements a radiation efficiency is determined. The theoretical plate responce is calculated using both classical and Mindlin–Timoshneko plate theory and is shown to agree well with experimental measurements. Radiated sound power is calculated for each mode of interest by solving the wave equation in oblate spheroidal coordinates at the plate surface. These calculations are verified by direct evaluation of the Rayleigh integral in the farfield. Good agreement is obtained between experimentally measured radiation efficiencies and theoretical predictions. Small discrepancies between theory and experiment are discussed.

Subject Classification: [43]20.55, [43]40.24, [43]35.65.
On parametric source aperture factors
Authors: Moffett Mark B. , Mellen Robert H.
Published: October 2005

It is well known that the beam pattern of a parametric acoustic source whose difference frequency is generated largely within the nearfield of the primary beam includes a multiplicative aperture factor that can be important at large angles when ka≳1 (k is the difference frequency wave number, a is the aperture radius). Not so well known, however, is the fact that the same aperture factor arises in the case of a spherically spreading, conical primary beam of finite initial aperture. The importance of the aperture size in determining the off-axis behavior of parametric sources is discussed.

Subject Classification: [43]25.35; [43]20.30; [43]30.75.
Alternative test method for evaluating impact noise
Authors: Schultz Theodore J.
Published: October 2005

The current method of measuring impact noise transmission involves the use of a standard hammer machine to produce a series of impact on the floor-ceiling structure, and the measurement of the resulting noise produced in the room below. The method has been criticized on the ground that ratings based on the test data correlate poorly with the subjective judgments of people listening to real-life impacts on the same floors. An alternative test method is proposed that uses a modified hammer machine whose internal impedance, intensity of impact, and striking frequency simulate those of real footfalls. The new method involves several changes from the present standard: short-term rms impact sound levels are measured instead of long-term rms levels; no normalization for the sound absorption of the receiving room is required; since the short-term levels are higher than the long-term levels usually measured, background noise is less of a problem than for the existing method. These proposed changes based on recent studies are expected to improve the correlation between test data and subjective judgments of floors.

Subject Classification: [43]55.80; [43]50.45.
Identification of random auditory waveforms. III. Effect of interference
Authors: Pollack Irwin
Published: October 2005

The identification of specific random waveforms, imbedded within random interference, was examined. Backward interference (interference after the specific waveform) was more effective than forward interference (interference before the specific waveforms). The accuracy of identification with combined interference (interference before and after the specific waveforms) is approximated by an independence model of interference. Under the present test conditions, interference with the identification of specific random waveforms is interpreted to be more nearly related to the interruption of auditory processing than to the masking of signal audibility.

Subject Classification: [43]65.58, [43]65.75, [43]65.52.
Speech sound discrimination by monkeys and humans
Authors: Sinnott J. M. , Beecher M. D. , Moody D. B. , Stebbins W. C.
Published: October 2005

Old World monkeys were trained with an operant conditioning technique to discriminate the natural speech sounds /ba/–/da/ and transferred to synthetic speech. Human and monkey difference thresholds for formant transitions were then compared along a seven-step /ba/–/da/ continuum. Monkeys were not as sensitive as humans to differences in formant transition: the just noticeable difference for monkeys was about 320 Hz, and for humans, about 160 Hz. Although humans were more adept at intraphonemic discriminations than monkeys, their latencies to stimulus changes revealed evidence of ’’categorical perception’’ of the continuum: While latencies for the monkeys increased linearly as stimulus difference was decreased, human latencies were essentially constant for all interphonemic comparisons, but increased sharply for intraphonemic comparisons. We view these data as evidence for (a) similar sensory capacities in monkeys and humans, but (b) unique speech processing capacities in humans.

Subject Classification: [43]65.75; [43]70.30; [43]80.50.
An investigation of speaker height and weight identification
Authors: Lass Norman J. , Davis Margaret
Published: October 2005

The purpose of this investigation was to determine if listeners were capable of speaker height and weight identifications from recorded speech samples. A standard prose passage was recorded by 30 speakers, 15 females and 15 males. A master tape containing the randomly arranged recorded readings of all speakers was played to a group of 30 subjects for speaker height and weight identification purposes. All subjects participated in two experimental sessions. In one session they were asked to determine the height of each of the speakers on the tape, and in another session weight judgments were made. The order of presentation of the height and weight tasks was randomized so that 15 subjects made height judgments first while 15 subjects made weight judgments first. A multiple-choice response sheet containing four choices for the judgment of height and weight for each speaker was provided. Results indicate that the subjects were capable, with slightly better than chance guessing accuracy, of identifying the heights of male and female speakers and the weights of male speakers when presented with only their recorded speech samples. Implications of these findings and suggestions for future research are discussed.

Subject Classification: [43]70.30.
A method for the experimental evaluation of the acoustic characteristics of an engine exhaust system in the presence of mean flow
Authors: Kathuriya M. L. , Munjal M. L.
Published: October 2005

The paper deals with an exact analysis of standing waves in an impedance tube with mean flow. A method is offered for the experimental evaluation of the various wave parameters. Navier–Stokes equations have been solved for evaluating the volume velocity taking into account mean flow, viscosity, etc. The engine exhaust system has been characterized as an acoustic source with an acoustic pressure and internal impedance. A method is suggested for the evaluation of these hypothetical parameters using the exhaust pipe as an impedance tube.

Subject Classification: [43]85.20; [43]20.40.
Hearing protector rating
Authors: Behar Alberto , Taibo Lucía , Raitzin Carlos
Published: October 2005

A direct comparison between the attenuation of different hearing protectors becomes difficult because it involves curves instead of numbers. Following the well-known technique developed in building acoustics concerning the rating of sound attenuation of partitions by using standard profiles, a new method for rating hearing protectors is proposed.

Subject Classification: [43]85.88.
Optimizing the monotone performance of electrodynamic drivers using tubular couplers
Authors: Finch R. D. , Higgins P. W.
Published: October 2005

A theory is presented for the design of resonant cylindrical couplers to be used with electrodynamic transducers to produce intense monotone signales in air. It is shown that for a given transducer there are different couplers which maximize radiation efficiency, or maximize radiated power, or which produce ρc loading in a connecting tube. The latter coupler loads the transducer as if it were connected to an infinitely long tube of the same diameter as the connecting tube. Several commerical transducers are examined to determine their radiation performance characteristics when loaded by suitable couplers. It is concluded that transducers are available which, when properly loaded by a cylindrical coupler, are capable of meeting the radiation requirements for devices such as an acoustic detection and ranging system. For example, a 200 Welect-rated commerical transducer may be made to radiate approximately 100 Wacoust when connected to a correctly designed quarter-wavelength cylindrical coupler.

Subject Classification: [43]85.40, [43]85.42.
Underwater acoustic scatter channels with several bounces
Authors: Tuteur Franz B.
Published: October 2005

This paper deals with scattering channels involving signal paths that are reflected several times from the boundary on their way from the transmitter to the receiver. The transmitted signal is a single-frequency sine wave, and the surfaces from which it is reflected are regarded as being statistically independent. Therefore the autocorrelation function of the received signal has a very simple form consisting mainly of the product of the characteristic functions of the various reflecting surfaces.

Subject Classification: [43]30.20; [43]30.40.
Dead-zone limiter: An application of conditional tests in nonparametric detection
Authors: Kassam Saleem A. , Thomas John B.
Published: October 2005

The concept of a conditional statistical test is applied to obtain a nonparametric detector based on the dead-zone limiter nonlinearity. The resulting detector is easily implemented, and its performance is shown to be superior to that of the sign detector for both large and small samples.

Subject Classification: [43]60.20,[43]60.30.
Mode theory of wave propagation in a bilinear medium: The WKB approximation
Authors: Hall Marshall
Published: October 2005

Normal-mode calculations are made of wave propagation in a bilinear medium with a free surface (the surface duct). The WKB approximation is used. In the usual way, the integral expression for the field is transformed into an infinite series of the residues (normal modes) of the integrand at its poles (eigenvalues). Approximations for the eigenvalues of the trapped normal modes are obtained from WKB formulas. The eigenvalues of the untrapped modes are obtained by quadratic extrapolation of the eigenvalues of the trapped modes. The accuracy of the real part of the eigenvalues of all modes is improved by taking into account the imaginary part when solving the characteristic equation. On comparing a number of WKB calculations of transmission loss with exact calculations, it is found that when there is little fine structure in the transmission loss curve, the WKB result is a good representation of the exact result. When there is significant fine structure, however, the WKB results are often in error by several decibels, and occasionally by up to 20 dB.

Subject Classification: [43]30.20; [43]20.15; [43]30.50.
Age as a factor in susceptibility to hearing loss: Young versus adult ears
Authors: Price G. Richard
Published: October 2005

In order to test the relative susceptibility of young and adult ears to loss from intense stimulation, losses in round window cochlear microphonic (CM) sensitivity and hair cell losses were compared in series of experiments using 52 eight-week old kittens and 59 adult cats. In acute experiments, ears of deeply anesthetized animals were exposed to 50 min of 5.0-kHz pure tone stimulation at that intensity necessary to produce a maximum CM output (MAX+0), or 10 dB(MAX+10) or 30 dB(MAX+30) higher than that. In chronic experiments, similar measures were made and the animals were allowed to recover for six weeks before their sensitivity was remeasured and their cochleas examined by surface preparation histology. Losses were the same at MAX+0, but at MAX+10 the kittens lost significantly more sensitivity than the cats. At MAX+30 the losses were large (45–50 dB) but not significantly different. The chronic experiments showed that some CM recovery did occur and that hair cell losses were orderly and generally confined to the areas of the basilar membrane involved in the displacement pattern for a 5.0-kHz tone.

Subject Classification: [43]65.64, [43]65.40.
Noise-intensity discrimination: Effects of bandwidth conditions and mode of masker presentation
Authors: Schacknow Paul N. , Raab David H.
Published: October 2005

Noise-intensity discrimination was studied as a function of both signal and masker bandwidth. Five bandwidths of noise—ranging from 100 to 10 000 Hz—were employed. Maskers were presented at each of three spectrum levels (5, 25, and 45 dB re 0.0002 μbar). Discrimination thresholds were relatively unaffected by changing bandwidth over a two-decade range when the signal and masker were filtered together, with either continuous or gated presentation of the masker. When the masker bandwidth was greater than that of the signal, the reciprocity between signal power density and signal bandwidth was found to be 5 dB per log unit of bandwidth with continuous maskers and 5–10 dB (depending upon level) with gated maskers. The results were compared with predictions of energy-detector models of noise-intensity discrimination. Modifications of simple energy-detection schemes were discussed.

Subject Classification: [43]65.58, [43]65.75, [43]65.50; [43]50.70.
Identification of vowels excerpted from /l/ and /r/ contexts
Authors: Bond Z. B.
Published: October 2005

Two experiments were conducted investigating the identifiability of vowels excerpted from context. Five phonetic contexts were investigated: neutral (h-d), initial and final /l/, and initial and final /r/. Vowels were excerpted from these contexts by computer and presented to subjects for identification. The consonantal contexts of initial and final /r/ and /l/ affected the identification of the excerpted vowels in various systematic ways, as compared with the identification patterns of vowels excerpted from the neutral context.

Subject Classification: [43]70.30, [43]70.40.[43]70.62.
Separation of speech from interfering speech by means of harmonic selection
Authors: Parsons Thomas W.
Published: October 2005

A common type of interference in speech transmission is that caused by the speech of a competing talker. Although the brain is adept at clarifying such speech, it relies heavily on binaural data. When voices interfere over a single channel, separation is much more difficult and intelligibility suffers. Clarifying such speech is a complex and varied problem whose nature changes with the moment-to-moment variation in the types of sound which interfere. This paper describes an attack on the principal subproblem, the separation of vocalic speech. Separation is done by selecting the harmonics of the desired voice in the Fourier transform of the input. In implementing this process, techniques have been developed for resolving overlapping spectrum components, for determining pitches of both talkers, and for assuring consistent separation. These techniques are described, their performance on test utterances is summarized, and the possibility of using this process as a basis for the solution of the general two-talker problem is briefly considered.

Subject Classification: [43]70.62, [43]70.60, [43]70.65.
Effects of selected vocal disguises upon spectrographic speaker identification
Authors: Reich Alan R. , Moll Kenneth L. , Curtis James F.
Published: October 2005

This research was designed to investigate the effects of selected vocal disguises upon spectrographic speaker identification. The experiment consisted of open-trial, spectrogram-matching tasks with 15 ’’reference’’ and 15 ’’matching’’ speakers. The speakers produced two sentence sets in six different ways: (1) normal-speaking mode, (2) old-age disguise, (3) hoarse disguise, (4) hypernasal disguise, (5) slow-rate disguise, and (6) free disguise of his own choosing. The reference spectrograms were always undisguised speech samples; the matching spectrograms were either disguised or undisguised. Four trained spectrographic examiners completed the matching tasks. The results revealed that the examiners were able to match speakers with a moderate degree of accuracy (56.67%) when there was no attempt to vocally disguise either utterance. The inclusion of disguised speech samples in the matching tasks significantly interfered with speaker-identification performance. However, certain voice disguises were more effective than others. In addition, certain speakers were considerably more difficult to identify than others. In summary, this investigation did not substantiate prior claims that spectrographic speaker identification is unaffected by attempts at disguising one’s voice.

Subject Classification: [43]70.65, [43]70.40.
Calibration data for a circumaural headset designed for hearing testing
Authors: Michael Paul L. , Bienvenue Gordon R.
Published: October 2005

Standard reference threshold levels for the new Telephonics circumaural headset using TDH−39 and TDH−50 earphones have been measured. Because the circumaural headset cannot be mounted meaningfully in the same suspension with a conventional supra-aural assembly, it was necessary to perform loudness balancing at threshold. The circumaural headset, furthermore, cannot be calibrated on the standard, NBS-9A coupler. Thus, it was necessary to develop a new coupler and to refine a new coupler measurement procedure. Data on the comparative attenuation and the subjective voltage and power sensitivities of the two headset designs are reported. Objective data from coupler measurements are also reported. Implications of these findings are discussed and reference-threshold sound-pressure levels for the two headset types using both the TDH−39 and the TDH−50 earphones are reported. In general, it was observed that the clincial use of the new Telephonics circumaural headset affords significantly greater attenuation of background noise and more consistent threshold responses than are seen with the conventional, supra-aural headset. Also, the circumaural earphone assembly can be calibrated on a flat-plate coupler with a consistency comparable to that found in calibrating the standard, supra-aural headset on an NBS-9A coupler.

Subject Classification: [43]85.86; [43]65.80.
Comments on ’’Measurement of frequency response and the multiple coherence function of the noise generation system of a diesel engine’’ [J. Acoust. Soc. Am. 58, 635–642 (1975)]
Authors: Holmes P. J. , Mercer C. A.
Published: October 2005

The main claim of a recent paper on diesel engine noise by Chung, Crocher, and Hamilton is questioned. In particular we discuss the influence of unmeasured correlated noise sources on the coherence technique used their paper.

Subject Classification: [43]50.50; [43]60.20.
Reply to ’’Comments on ’Measurement of frequency response and the multiple coherence function of the noise generation system of a diesel engine’ ’’ [J. Acoust. Soc. Am. 60, 951–952 (1976)]
Authors: Chung J. Y. , Crocker M. J. , Hamilton J. F.
Published: October 2005

Explanations are given for the difficulties encountered by Holmer and Mercer concerning unmeasured correlated noise sources.

Subject Classification: [43]50.50, [43]60.20.
Ambient-noise horizontal directionality measurements with linear arrays
Authors: Wilson J. H.
Published: October 2005

A Fourier analysis method is developed for estimating the symmetric part of the horizontal ambient noise field about a single heading from noise measurements by a linear array. The antisymmetric part of the noise field about the array cannot be measured due to the cylindrical symmetry of the array. In this method, the ambient noise field is expanded in a Fourier series and the Fourier coefficients are determined from the measurements. The number of Fourier coefficients that can be determined is equal to the number of nonoverlapping beams since the beam pattern acts as a spatial low-pass filter. This Fourier analysis method is superior to the procedure of dividing the array beam data by the beamwidth, especially in highly anisotropic noise fields. The full beam pattern of the array is used in the Fourier analysis method while dividing by the beamwidth automatically assumes infinitely thin beams. Dividing the array beam data by the beamwidth is justified only in isotropic noise fields. The Fourier series method is extended to estimate the antisymmetric part of the noise field about an array heading from measurements made at two array headings. Knowing the symmetric part of the noise field about two array headings allows the estimation of the antisymmetric part of the noise field about either heading if the noise field is stationary.

Subject Classification: [43]60.28, [43]60.30; [43]50.10.
Role of duration in disambiguating syntactically ambiguous sentences
Authors: Lehiste Ilse , Olive Joseph P. , Streeter Lynn A.
Published: October 2005

The present study investigated whether listeners use the prosodic variable, duration, to disambiguate syntactically ambiguous sentences. Some of the sentences’ meanings could be represented by two distinct syntactic bracketings, e.g., ’’The hostess [[greeted] [the girl] [with a smile].’’ and ’’ The hostess [greeted] [[the girl] [with a smile.]].’’ Other sentences, while ambiguous, had a common syntactic bracketing, e.g., ’’[German teachers] visit Greensboro.’’ In this experiment the duration of words corresponding to ambiguous constituents of the sentences or containing ambiguous boundaries of the constituents was varied systematically. Subjects listened to the sentences and selected one of the two meanings. The results indicated that only sentences in which the two meanings were represented by two distinct syntactic bracketings were reliably disambiguated by durational cues. It is suggested that when the interstress interval spanning a major syntactic boundary is increased, listeners perceive the boundary’s presence.

Subject Classification: [43]70.30, [43]70.70.
Addendum to ’’Propagation in an inversion and reflection at the ground’’ [J. Acoust. Soc. Am. 59, 278–282 (1976)]
Authors: Embleton T. F. W. , Thiessen G. J. , Piercy J.
Published: October 2005

The relevance of some earlier work in underwater acoustics to the subject paper is noted. Similar basic theory has been applied in underwater acoustics to the study of the location and shape of caustics caused be bundles of ray paths, and in the air acoustics to calculation of sound levels resulting from propagation via multiple paths that have a degree of coherence, in a turbulent medium, which depends on their separation.

Subject Classification: [43]28.40.
Flow excitation and coupling of acoustic modes of a side-branch gravity in a duct
Authors: Ingard Uno , Singhal Vijay K.
Published: October 2005

As part of a broader study of flow noise in ducts, we have investigated the flow excitation of the acoustic modes of a side-branch cavity in a duct and report on evidence of coupling between the different cavity modes and between the cavity modes and the axial modes in the main duct.

Subject Classification: [43]28.65; [43]20.45.
Comments on ’’Sound propagation through a fluctuating stratified ocean: Theory and observation’’ [J. Acoust. Soc. Am. 59, 818–838 (1976)]
Authors: McCoy John J.
Published: October 2005

Some assumptions and restrictions of the proposed propagation model are discussed.

Subject Classification: [43]30.30, [43]30.20.
Reply to ’’Comments on ’Sound propagation through a fluctuating stratified ocean: Theory and observation’ ’’ [John J. McCoy, J. Acoust. Soc. Am. 60, 1216–1217 (1976)
Authors: Munk W. H. , Zachariasen F.
Published: October 2005

Useful theeorectical estimates for comparison with experiments can be obtained within the limitations of the Rytov formula.

Subject Classification: [43]30.20, [43]30.30.
Guidelines for the planning and preparation of illustrated technical talks
Authors: Hubbard Harvey H.
Published: October 2005

Guidelines are presented for the preparation of illustrated talks which are audience oriented and which are aimed at the efficient transfer of technical information. Early decisions concerning the required number of slides are helpful in initial planning for a good-quality talk. Detailed considerations are the establishment of limited objectives, selection of appropriate slide material, development of a text which is well coordinated with the slides, and accurate timing.

Subject Classification: [43]10.60.
Diffusion loss in a stratified sound channel
Authors: Mellen R. H. , Browning D. G. , Goodman L.
Published: October 2005

Low-frequency propagation measurements in sound channels often show a frequency-independent excess loss that is evidently caused by internal scatter from large-scale inhomogeneities. Using the Garrett–Munk internal wave spectrum (GM 75) as the scattering model, we have obtained an approximate solution of the ray-diffusion equation on the deep sound-channel axis. The estimated attenuation coefficient, ∠5×10−4 dB/km, is consistent with the smaller experimental values reported.

Subject Classification: [43]30.20; [43]20.20; [43]30.40.
Observations of volume scattering strength in the Northeast Atlantic
Authors: Smailes I. C.
Published: October 2005

Measurements of volume backscattering strength have recently been made to a depth of 1500 m in the Northeast Atlantic. Scattering layers with strengths of −80 dB and −70 dB have been found at depths of approximately 500 and 1000 m, respectively. The layer at 1000 m has been shown to comprise fish shoals distributed with a density of 3.2 in 108 m3, each shoal having a target strength of about −6 dB and comprising about 50 fish. Each fish is thought to have a swimbladder resonant at 2 kHz at 1000 m and hence to have a radius of 1.6 cm. The shoals have been shown to vary with geographical location but not with the time of day, 1000 m being about the maximum depth of daylight penetration. The layer at 500 m does not vary much with geographical location but does exhibit diurnal variations due to the well-known vertical migration of fish in a diurnal cycle.

Subject Classification: [43]30.40.
Reflected and lateral waves for the Sommerfeld model
Authors: Stickler D. C.
Published: October 2005

The Sommerfeld model, a constant-density isospeed half space over a second constant-density isospeed half space, has offered extensive insight into the role of the ocean bottom in acoustic propagation by exploiting properties of the ground or lateral wave and the specularly reflected waves. This paper presents some new results for this model. A uniform asymptotic expansion is obtained for the source and receiver on the interface, which reduces to the exact solution as either the density ratio or the sound-speed ratio approaches unity. In addition, this result shows the ground or lateral wave decays initially—not like 1/kr2, the classical result, but like 1/r, and as the index ratio approaches unity this region increases. For the source and receiver above the interface, the reflected fields are expressed in a uniform expansion involving the parabolic cylinder functions. Away from the critical ray these expressions reduce to the usual specular and lateral fields. The expressions reduce to the interface results and are not singular as the sound-speed index approaches unity, and confirm the above decay predictions for the lateral wave.

Subject Classification: [43]30.20, [43]30.30; [43]20.15.
On the parametric model of loose bonding of elastic half spaces
Authors: Banghar A. R. , Murty Gurajada S. , Raghavacharyulu I. V. V.
Published: October 2005

In this paper, a unified approach of the possible bondings between two elastic half spaces is studied. Assuming that two elastic half spaces are separated by a Newtonion viscous liquid layer of thickness H, and of shear viscosity coefficient η, the condition for the existence of interfacial waves propagating along the layer is derived. This condition is separately examined in the three possible limits of η/H when H→0: (1) η is finite or tends to zero such that η/H→∞; (2) η tends to zero such that η/H→0; and (3) η tends to zero such that η/H≠0 finite. It is established that the case (1) corresponds to welded contact of solid half space studied by Stoneley and cases (2) and (3) correspond, respectively, to smooth and loosely bonded interface of solid half spaces. This theory established that η/H can be used under the above-stated limits as a measure of bonding at the interface, hence its inverse as a measure of smoothness.

Subject Classification: [43]35.24; [43]20.15.
Finite-element simulation of acoustic filters of arbitrary profile with circular cross section
Authors: Kagawa Yukio , Omote Toshio
Published: October 2005

A finite-element approach is developed to simulate acoustic transmission systems of arbitrary profile with circular cross section. Sound-transmission characteristics are considered in which axisymmetric radial modes are taken into account. Some simple examples of acoustic filters with various profiles are calculated for which the numerical values are compared with the measured ones, as well as those of the one-dimensional models based on an electrical transmission line analogy. The procedure is a valid and powerful means to cope with filters of any profile and may pave the way to solutions of problems of this kind.

Subject Classification: [43]20.40; [43]85.32..
Example of acoustic model evaluation and data interpretation
Authors: Hanna J. S.
Published: October 2005

Explosive data from a carefully controlled transmission-loss measurement in the Northeast Atlantic Ocean are used to evaluate, in detail, the capability of the AESD parabolic equation model. The analysis is performed on a path-by-path basis by comparison of computed (using a ray-tracing program) and measured travel-time differences. Sensitivtiy studies show that residual discrepancies could be attributed to uncertainties in source detonation depth and the assumption of piecewise-linear bathymetry. The data show an arrival with no ray-tracing counterpart; evidence, based upon its mean speed of propagation and the frequency dependence of its energy content, is presented to argue that it is an arrival ducted in the main sound channel. The behavior of this arrival with range is determined by the range dependence of the sound-speed environment.

Subject Classification: [43]30.20; [43]20.20.
Estimates of underwater sound (and infrasound) produced by nonlinearly interacting ocean waves
Authors: Hughes B.
Published: October 2005

Estimates of sound (and infrasound) spectral levels are given using a theoretical model of acoustic production based on quadratic interactions of oppositely traveling ocean waves, and incorporating present day surface wave spectral models. It is shown that reasonable agreement with measurements exists for frequenices less than 10 Hz but predictions are 10–15 dB low and have the wrong spectral shape at higher frequencies.

Subject Classification: [43]30.40; [43]20.15; [43]30.70; [43]28.65.
Experimental investigation of acoustic transmission from air into a rough ocean
Authors: Lubard Stephen C. , Hurdle Patrick M.
Published: October 2005

An experimental investigation to determine the acoustic transmission from a source in air to a hydrophone in a wind roughened ocean at shallow depression angles is described and the results presented. This experiment was conducted at the NUC Oceanographic Tower in 18-m-deep water. Data were obtained for acoustic frequencies of 500–4000 Hz and wind speeds of 3–15 knots. Short pulses of sound were used in order to distinguish the direct path from the bounce paths. The mean energy at the hydrophone was obtained by averaging the direct path energy over many independent pulses. The data show that more energy reaches the hydrophone in the rough ocean than predicted by the smooth surface theory, with the excess increasing for the shallower depression angles. The data also show that the transmission increases with increasing source frequency and ocean roughness and is independent of source altitude for the conditions considered. The experimental results are compared with a geometric rough surface model and show good agreement.

Subject Classification: [43]30.20, [43]30.25; [43]20.20.
Theory and numerical calculation of the acoustic field produced in metal by an electromagnetic ultrasonic transducer
Authors: Kawashima Katsuhiro
Published: October 2005

The equations for calculating the acoustic field produced within a nonmagnetic metal by an interaction of eddy current with a static magnetic field were obtained on the assumptions that (1) an ultrasonic wave is generated by the electromagnetic force through classical and macroscopic phenomena; (2) the electric, magnetic, and elastic properties of the metal are linear, isotropic, and homogeneous throughout the metal, which occupies semi-infinite space; (3) the whole system is axially symmetric; and (4) eddy currents and elastic waves show a steady-state sinusoidal variation. The acoustic field produced by a specific electromagnetic ultrasonic transducer with axial symmetry was calculated numerically, and the results showed a well-defined ultrasonic wave beam, which was narrower than had been expected from the size of the transducer.

Subject Classification: [43]35.60; [43]85.48.
Scattering of normally incident Rayleigh waves by thin strips
Authors: Simons Donald A.
Published: October 2005

The plane-strain problem of the scattering of a Rayleigh wave by a thin surface strip is formulated in terms of a pair of coupled integral equations, one of which is singular. The equations are equivalent to a set of boundary conditions which represent the effect of the strip on the substrate. A technique based on Gaussian approximation of the integrals is employed to solve the equations numerically for two representative cases over a range of wavelengths. The power reflection and radiation coefficients and the phase of the reflected surface wave are evaluated for the representative cases.

Subject Classification: [43]35.54; [43]20.15, [43]20.30.
Acoustical analysis, testing, and design of flow-reversing muffler chambers
Authors: Young Cheng-I James , Crocker Malcolm J.
Published: October 2005

The transmission loss characteristics of flow-reversing muffler chambers were predicted by a numerical approach based on the finite element method. The theoretical model developed is described in this paper; its validity is established experimentally with a number of different chambers. The standing wave method was used to measure transmission loss and measurements were conducted with and without steady air flow. Depending on the inlet and outlet configurations, the flow-reversing chambers have two completely different transmission loss characteristics, one is similar to that for two sample expansion chambers in series and the other is similar to that for a side-branch resonator. Using the theoretical model developed, transmission loss curves were calculated for a large number of different flow-reversing chamber dimensions.

Subject Classification: [43]50.30, [43]50.40.
Scaling loudness, noisiness, and annoyance of community noises
Authors: Berglund Birgitta , Berglund Ulf , Lindvall Thomas
Published: October 2005

The contribution of type and sound levels of community noises to the perception of loudness, noisiness, and annoyance was studied in a laboratory situation. The psychological attributes were precisely defined to the 30 observers, the method of magnitude estimation was used for scaling the attributes, and the scales were calibrated to a common unit of measurement. It was demonstrated that observers in carefully designed laboratory experiments are able to use and produce scales of loudness, noisiness, and annoyance for community noise. The relationships between the attributes were satisfactorily described by linear functions, the parameters being specific to the type of community noise. In general, community noises are judged to be more noisy (or annoying) than loud although the importance of noisiness relative to loudness varies with type of noise as well as loudness level. A linear model is suggested that describes community noises with regard to perceptual attributes. The model states that annoyance and noisiness are proportional to loudness, thus encouraging the viewpoint that psychoacoustical research may well concentrate on the attribute of loudness.

Subject Classification: [43]65.50, [43]65.52; [43]50.75, [43]50.20.
Method for estimating the audibility and effective loudness of sirens and speech in automobiles
Authors: Corliss Edith L. R. , Jones Frank E.
Published: October 2005

By using the parameters for the ear and the equations for a ’’communication theory’’ model of the behavior of the ear, a family of masking curves can be drawn up which one can apply to the conditions prevalent in automotive vehicles. From the behavior of the ear and its ability to resolve sounds in noise, estimates can be made of the conditions under which sirens and speech communications will be audible within motor vehicles moving in traffic, and some estimate can also be made as to their potential for attracting notice. These quantities can be read off by graphic techniques. Examples of their use are given.

Subject Classification: [43]65.50, [43]65.75, [43]65.58 [43]50.70.
Analysis of compound action potential responses to tone bursts in the human and guinea pig cochlea
Authors: Eggermont J. J.
Published: October 2005

In electrococholegraphy, compound action potentials (AP) are recorded from the human promontory and the guinea pig round window. High-pass noise masking and subtraction of AP responses at various high-pass cutoff frequencies give the narrow-band contributions to the whole nerve AP. Although the narrow-band contributions recorded from human and guinea pig ears differ essentially, this narrow-band concept makes it possible to derive a response area for a given type of stimulus, e.g., tone bursts. Within the response area, any combination of stimulus intensity and site on the cochlear partition evokes a detectable narrow-band response contributing to the whole-nerve AP. The main part of this contribution shifts basally the higher the stimulus intensity. Latency differences between responses from the various narrow bands are used to calcuate the traveling-wave velocity for the human cochlea, which ranges from about 20 m/sec at 10 kHz to 1 m/sec at 500 Hz. The amplitude and width of the narrow-band responses are closely related to the traveling-wave velocity in the narrow band. It is argued that the response area and the narrow-band-response concept offer a means to relate electrocochleography in the human subject to the results obtained from single-fiber studies in the normal and pathological animal cochlea.

Subject Classification: [43]65.26, [43]65.20, [43]65.22, [43]65.40.
Subjective equivalence of sinusoidal and random whole-body vibration
Authors: Griffin Michael J.
Published: October 2005

An experiment conducted to compare the discomfort produced by whole-body sinusoidal vibration with that produced by one-third-, one-, and three-octave vibration spectra is described. Seated subjects were required to adjust the level of a variable test vibration such that it produced a degree of discomfort similar to that caused by a 10-Hz sinusoidal vertical whole-body vibration at 0.75 m/sec2 rms. The test stimuli were nine sinusoidal vibrations (at 3.15, 4.00, 5.00, 6.30, 8.00, 10.00, 12.50, 16.00, and 20 Hz); nine one- third-octave bands of random vibration centered at the above frequencies, three single-octave bands (centered at 4.00, 8.00, and 16.00 Hz) and a three-octave band (centered at 8.00 Hz). The results obtained by this method indicate that the mean equivalent discomfort produced by all the random motions employed in the experiment may be predicted by weighting the vibration spectra with a filter network. A suitable filter response is that determined from a contour of equal comfort for sinusoidal or one-third-octave random vibration.

Subject Classification: [43]65.70.
Psychophysical tuning curves of chinchillas
Authors: McGee Therese , Ryan Allen , Dallos Peter
Published: October 2005

Psychophysical tuning curves were obtained on normal chinchillas using a shock-avoidance technique. Curves were measured at several levels and frequencies of the signal, and both simultaneous and forward masking were employed. The chinchilla curves were found to be similar to those obtained with human subjects by other researchers. Also, a comparison of the chinchilla psychophysical tuning curves with cat physiological tuning curves shows that the two are similar in shape and sharpness of tuning.

Subject Classification: [43]65.58, [43]65.68, [43]65.35, [43]65.75; [43]80.50.
Phenomenological model for two-tone suppression
Authors: Sachs Murray B. , Abbas Paul J.
Published: October 2005

A model relating discharge rate in single auditory-nerve fibers to parameters of a two-tone stimulus is presented. We consider cases where one tone is at fiber characteristic frequenfcy (CF) and the other tone produces two-tone suppression. The last stage in the model is a saturating nonlinearity. For the CF tone presented alone, the input to this nonlinearity is the CF amplitude; in the two-tone case, the CF amplitude is attenuated by a factor which depends only on the suppressor-tone amplitude and frequency. The model serves to relate a number of two-tone studies. In particular, it predicts our recently reported differences in two-tone suppression for the cases of suppressor frequencies above and below fiber CF.

Subject Classification: [43]65.35, [43]65.42.
Model for auditory localization
Authors: Searle C. L. , Braida L. D. , Davis M. F. , Colburn H. S.
Published: October 2005

A mathematical model based on statistical decision theory has been devised to represent the human auditory localization task. The known localization cues have been represented as Gaussian random variables, so that their interaction in a given experiment can be analyzed (and predicted) along the lines of classical detection/estimation theory. We have applied this technique to most of the horizontal and vertical localization experiments reported in the literature during the past ten years, encompassing over 200 subjects and 20 000 trials. Using a nonlinear regression program we have been able to estimate the standard deviations of four of the auditory localization cues, allowing objective comparison of their relative accuracy. The resulting model provides a relatively good fit to the published results on 40 localization experiments.

Subject Classification: [43]65.62, [43]65.58, [43]65.35.
Factors in the discrimination of tonal patterns. II. Selective attention and learning under various levels of stimulus uncertainty
Authors: Watson Charles S. , Kelly William J. , Wroton Henry W.
Published: October 2005

This is the second in a series of articles in human listeners’ abilities to discriminate between word-length tonal sequences, or ’’patterns.’’ The first article reported that frequency resolution, by highly trained listeners, is four to five times more accurate for high-frequency, late-occurring components of such sequences than for low−frequency early components [Watson, Kelly, and Benbasset, J. Acoust. Soc. Am. 57, 1175–1185 (l975)]. These effects, which are similar to described as ’’recognition masking’’ or ’’informational masking’’ by other authors, have now been shown to be strongly dependent on the degree of trial-to-trial stimulus uncertainty of the psychophysical procedure in which they are measured. When stimulus uncertainty is reduced to its psychophysical minimum, frequency resolution for any component of a tonal sequence is only slightly less accurate than for isolated tones. Previous reports of recognition masking this may reflect limitations imposed by those more dynamic parts of the sensory process concerned with memory and attention, rather than information loss in the more static peripheral auditory system.

Subject Classification: [43]65.22, [43]65.75, [43]65.64, [43]65.58.
Interferometer method for the measurement of the ultrasonic properties of solids
Authors: Kritz J.
Published: October 2005

An interferometer method for the measurement of the ultrasonic propagation velocity and absorption coefficient in solids is described. The method provides a simple procedure to permit accurate evaluation using standard laboratory test instruments. Impedance and frequency measurements at successive maxima and minima are made using a half-wave transducer coupled to a short sample. Experimental results of velocity versus temperature and absorption coefficient for polystyrene at 2 MHz are given and the results compared with other published values.

Subject Classification: [43]35.80, [43]35.26.
Design approach for quadrature sampled digital bandpass filters
Authors: Kerr D. E. , Lengyel M. W.
Published: October 2005

A design procedure is developed for digital bandpass filters having quadrature sampling. The design process is developed from Nth-order bandpass sampling reconstruction theory. These filters possess properties that satisfy the requirements of a class of digital filter problems.

Subject Classification: [43]60.20; [43]85.32.
Lateralization of complex waveforms: Effects of fine structure, amplitude, and duration
Authors: Nuetzel John M. , Hafter Ervin R.
Published: October 2005

In recent years there has been an increased interest in the use of interaural time as a cue for lateralization at high frequencies. Our study examines this question using AM complexes with carriers of 1800, 2400, 3000, 3600, 3900, 4200, and 4500 Hz, modulated at 300 Hz and interaurally delayed. The findings indicate that (a) the ability to lateralize these stimuli does not depend on low-frequency distortion, since this ability remains despite the presence of intense low-frequency masking; (b) the task is easier when the entire waveform, rather than just the modulation envelope, is delayed, though this difference seems to decline with practice; (c) the effects of stimulus amplitude and duration on the detection of interaural time differences are reminiscent of those observed with pure tones, although ongoing time differences may be more fully utilized with AM signals; and (d) lateralization declines with interaural carrier frequency discrepancy. We were unable to obtain lateralization of AM complexes at one ear against pure tones (at the modulation frequency) at the other. This strengthens the argument that all stimulus information used is carried in high-frequency channels.

Subject Classification: [43]65.62.
On the mechanics of vocal-fold vibration
Authors: Titze Ingo R.
Published: October 2005

The human vocal fold is treated as a continuous, transversally isotropic, bounded medium. The theory of viscoelasticity is applied to formulate the stresses, strains, glottal tissue impedance, and propagation characteristics for sinusoidal oscillation within the vocal-fold tissues. Incompressibility of the tissues leads to a biharmonic differential equation, the solution of which represents commonly observed modes of vibration. The energy dissipated in the tissues and the associated damping factors are calculated. Mode impedances of the tissues are calculated and lumped-model approximations of the system evaluated. The usual mass-spring models are shown to be inadequate in certain important cases, especially during vocal-fold closure and for modes in which vertical phase differences occur.

Subject Classification: [43]70.20.