bluuebunny/crossref_metadata_2025 huggingface dataset:
Aircraft community noise research and development; a historical overview
Authors: Blumenthal V. L. , Russell R. E. , Streckenbach J. M.
Published: October 2005

The paper summarizes noise-reduction research and development programs of The Boeing Company from the early 1950s to the present time. It discusses the background for each program and presents the end results obtained or progress made. Acoustic treatments are described that permit all current Boeing turbofan†powered commercial aircrafdt models to comply with applicable U.S. Government and international noise rules. Benefits attainable through noise-abatement operating procedures are included. The paper concludes with a discussion of unsolved problems that need attention by the scientific community to permit continuing reductions in aircraft noise.

Subject Classification: 50.40, 50.50, 50.55, 50.75.
Nose-reduction programs for DC-8 and DC-9 airplanes
Authors: Frasca R. L.
Published: October 2005

A summary review is presented of the results of current and recently completed noise-reduction programs for DC-8 and DC-9 airplanes. The relationship of these programs to other efforts by Douglas to develop quieter CTOL airplanes is briefly outlined. The engine/nacelle concepts studied were (1) application of nacelle acoustic treatment, (2) variable-area exhaust nozzles, (3) jet exhaust noise suppressors, and (4) engines with larger diameter new front fans. Acoustic analyses leading to the selection of certain engine/nacelle configurations are described, as well as design constraints which limit the noise-reduction capability of certain designs. Acoustic design features of the modified engine/nacelles are discussed along with estimates of the changes in aircraft community noise levels, as well as estimates of the changes in aircraft weight, performance, cost, and operational restrictions. The noise-reduction estimates for the DC-8 and DC-9 are based on ground runup and flyover noise tests. Comments are presented on the potential noise-reduction benefits, and associated aircraft operational problems, resulting from noise-abatement operating procedures.

Subject Classification: 50.40, 50.50, 50.30, 50.55, 50.75.
Loudness enhancement: monaural, binaural, and dichotic
Authors: Elmasian Robert , Galambos Robert
Published: October 2005

When one tone burst (Tc) precedes another (S1) by 100 msec, variations in the intensity of Tc systematically influence the loudness of S1. When Tc is more intense than S1, S1 is increased; and when Tc is less intense, S1 loudness is decreased. This occurs in monaural, binaural, and dichotic paradigms of signal presentation. When Tc and S1 are presented to the same ear (monaural or binaural) there is more enhancement with less intersubject variability than when they are presented to different ears (dichotic paradigm). Monaural enhancements as large as 30 dB can readily be demonstrated but decrements rarely exceed 5 dB. Possible physiological mechanisms are discussed for this loudness enhancement, which apparently shares certain characteristics with time-order error, assimilation, and temporal partial masking experiments.

Subject Classification: 65.50, 65.62.
Effects of high-pass filtering and of extraneous low-frequency energy on measurements of wall-pressure correlation functions
Authors: Mulhearn P. J.
Published: October 2005

The effects of extraneous high-frequency energy and of high-pass filtering to eliminate it on measurements of turbulent wall-pressure fluctuations are investigated using a model spectrum. It is concluded that under normal conditions, while the overall shape of the correlation functions is not greatly affected by these modest adjustments at low frequencies, changes in correlation values of the order of 50% will result at only moderatly large time delays or spatial separations.

Subject Classification: 28.65; 85.32; 60.20.
Aerodynamic noise from motor vehicles
Authors: Chanaud Robert C. , Muster Douglas
Published: October 2005

In motor vehicles there are two primary sources of aerodynamic sound: the engine-cooling fan and the interaction of either the entire vehicle or some of its components with the airstream created by vehicle movement. The mechanisms for sound generated by these sources are discussed in terms of the associated physical parameters (fan size, fan-blade design, cooling-air velocity and path, etc.; body configuration, interior design, etc.).

Subject Classification: 10.60; 50.50, 50.55.
Tire–road interaction noise
Authors: Leasure William A. , Bender Erich K.
Published: October 2005

The relative importance of tire noise to overall vehicle noise is established. A general description is then given of the tire engineering process and of tire structures. The important parameters influencing tire noise are discussed, based on presently available data, followed by an identification of unknown and contradictory areas. The basic mechanisms of tire-noise generation, although not well understood, are investigated largely from a theoretical viewpoint. Areas for future research and development are identified based on gaps in the existing physical data base and a rather primitive level of understanding of noise-generating mechanisms.

Subject Classification: 10.60; 50.50, 50.30.
Focusing properties of a solid four element ultrasonic lens
Authors: Folds D. L. , Hanlin J.
Published: October 2005

A multielement cylindrical lens fabricated from polystyrene and an unfilled silicone polymer has been developed with angular resolution in the order of 0.2 deg at 1000 kHz. Theoretical and experimental work shows the lens maintains good performance over a 20-deg field of view with insignificant temperature-induced defocusing in the 10 ° to 25 °C temperature range. Tolerance analyses completed during the lens design resulted in reasonable mechanical tolerances being required during fabrication.

Subject Classification: 30.85; 35.80.
Acoustic radiation from surfaces oscillating at large amplitude and small Mach number
Authors: Frost P. A. , Harper E. Y.
Published: October 2005

The purpose of this paper is to demonstrate that at small values of the Mach number a harmonically rich radiated field will result from the simple harmonic (sinusoidal) motion of an oscillating body when the amplitude of oscillation is large. An asymptotic solution of the equations of inviscid compressible flow is obtained which is valid in the small Mach number limit. To a given order of approximation, the effects of fluid nonlinearity (nonlinearity in the equations of motion and the equation of state) do not enter, and the harmonic distortion is due entirely to large-amplitude boundary motion. In higher approximations, where both the effects of boundary motion and fluid nonlinearity enter, the former effect can still control the amplitude of certain harmonics of the radiated acoustic field. The results are obtained by the method of matched asymptotic expansions, which is ideally suited for the purpose of distinguishing the harmonic distortion due to large displacements from that due to fluid nonlinearity. The method is used to make the connection between the field far from the source, and the nonpropagating hydrodynamic flow field near the oscillating body.

Subject Classification: 25.55; 20.15, 20.60.
Masking of tone by tone as a function of duration
Authors: Jeffress Lloyd A.
Published: October 2005

Consideration of a proposed electrical model of monaural detection leads to the suggestion that subjects listening to long-duration signals may respond on the basis of amplitude peaks. To eliminate such peaks, a 500-Hz tone was employed as both masker and signal. A two-interval, forced-choice procedure was used to determine the level required for 80% correct at each of several signal durations. The masker level was 60 dB SPL, and the signal was always in phase with the masker. Signal durations from 20 msec to 2 sec were employed. The results showed a slope of approximately −3 dB per doubling over the range from 20 msec to 1 sec. Detection at 2 sec tended to be worse than at 1 sec. The slope of 03 dB per doubling is steeper than has commonly been found with noise maskers, especially at the longer durations. The psychometric function exhibites a systematic change of slope with duration—steep for short durations and shallow for long.

Subject Classification: 65.35, 65.58, 65.75.
Speech perception by the chinchilla: discrimination of sustained ‖a‖ and ‖i‖
Authors: Burdick Charles K. , Miller James D.
Published: October 2005

Four chinchillas were trained to respond differently to sustained ‖a‖ and ‖i‖. The ensemble of vowels included two repetitions of each of the vowels by each of four talkers at each of three pitch levels for a total of 24 ‖a‖’s and 24 ‖i‖’s. The sound levels of the vowels were randomly changed from trial to trial over a 10-dB range. The animals easily transferred the training to a new set of vowels produced by 24 new talkers. Subsequently, the animals similarly transferred to synthetic ‖a‖’s and ‖i‖’s. The only relevant difference between the synthetic vowels was their formant structure, while there were irrelevant differences in their pitch contours. We conclude that the chinchilla can abstract some essential difference(s) between sustained ‖a‖ and ‖i‖ and ignore irrelevant variations of sound level, pitch level, pitch contour, and voice quality. These results are discussed in terms of perceptual learning and auditory concept formation.

Subject Classification: 70.30; 65.75; 80.50.
On the front cavity resonance and its possible role in speech perception
Authors: Kuhn G. M.
Published: October 2005

Spectrographic data are presented which suggest that it may be possible to estimate the frequency of the fundamental resonance of the cavity behind the mouth opening, the ’’front cavity resonance,’’ from information in the speech signal. It is shown that place of articulation information in the steady states, transitions, and bursts of F2 (or sometimes F3) can be reinterpreted to be information from the front cavity resonance. Furthermore, a number of synthesis results that have appeared anomalous when described in terms of numbered formants seem to find a coherent explanation in terms of the front cavity resonance. Implications for theories of speech perception include the possibility that an estimate of front cavity resonance frequency may serve for continuous articulatory reference.

Subject Classification: 70.20, 70.30.
Sound absorption measurements at 10–60 kHz in near-freezing sea water
Authors: Garrison G. R. , Francois R. E. , Pence E. A.
Published: October 2005

Sound propagation measurements at various frequencies between 10 and 60 kHz were made in April 1974 under the pack ice near Pt. Barrow, Alaska. With a stationary transmitter at mid-depth, a series of sound level versus depth profiles at ranges between 40 and 1300 m were obtained and used to calculate the absorption coefficient. Although the sound speed profile contained many small irregularities which caused undesirable fluctuations, it had no large features that would change the average intensity at the ranges and depths at which the sound was received. The average temperature and salinity were −1.6 °C and 32.3 0/00, respectively. The calculated absorption values in decibels per kiloyard were 2.5±0.5 at 10 kHz, 4.5±0.5 at 20 kHz, 8.3±0.5 at 30 kHz, 10.7±0.4 at 40 kHz, and 13.9±0.5 at 60 kHz. These values indicate a relaxation frequency, assumed due to MgSO4, of 27±5 kHz, a value much lower than that predicted by the Schulkin–Marsh equation, but about the same as that determined by Greene in similar low-temperature water.

Subject Classification: 30.20, 30.80; 35.24.
Simulation of multicorrelated random processes using the FFT algorithm
Authors: Wittig L. E. , Sinha A. K.
Published: October 2005

A technique for the digital simulation of multicorrelated Gaussian random processes is described. This technique is based upon generating discrete frequency functions which correspond to the Fourier transform of the desired random processes, and then using the fast Fourier transform (FFT) algorithm to obtain the actual random processes. The main advantage of this method of simulation over other methods is computation time; it appears to be more than an order of magnitude faster than present methods of simulation. One of the main uses of multicorrelated simulated random processes is in solving nonlinear random vibration problems by numerical methods of simulation. One of the main uses of multicorrelated simulated random integration of the governing differential equations. The response of a nonlinear string to a distributed noise input is presented as an example. nonlinear string to a distributed noise input is presented as an example.

Subject Classification: 45.40; 40.30, 40.22, 40.35.
Perceptual space for musical structures
Authors: Miller James R. , Carterette Edward C.
Published: October 2005

Individual subjects with or without musical training made similarity judgments of pairs of tones on a nine-point scale. Each subject was run in three or four sessions of 351 trials each. The tones had structures like those of musical instruments, being made of all 27 combinations of three dimensions, each at three levels. In Experiment 1, the dimensions were fundamental frequency F0, envelope, and relative amplitudes of harmonics. In Experiment 2, the dimensions were number of harmonics, envelope, and onset rate of harmonics. Analysis of data by means of multidimensional scaling showed a strong context effect. In Experiment 1, F0 had such high saliency that for most subjects no other dimension was present in perceptual space and thus no differences were found between musical and nonmusical subjects. By holding F0 constant in Experiment 2, subjects were able to use harmonic as well as envelope structure in judgments. Differences between musical and nonmusical subjects appeared, and we discuss the basis for these differences. For both experiments, the curve relating latency of response to similarity was parabolic and, although a given subject’s perceptual space changes little over successive runs, there is some evidence from Experiment 2 that musical subjects have the more stable space of perceptual dimensions.

Subject Classification: 65.52, 65.75; 75.10.
Amplitude behavior of the cubic difference tone
Authors: Schroeder M. R.
Published: October 2005

The nonlinearity of the basilar membrane motion observed by Rhode can be accounted for by assuming that the linear losses (proportional to the membrane velocity) are supplemented by nonlinear losses—particularly losses proportional to the velocity raised to the third power. In this paper, the consequences of such a nonlinear-loss law for the combination tone 2f1−f2 (the lower ’’cubic difference tone,’’ DCT) are examined. In agreement with experimental data, the amplitude of the CDT is found to approach a cube-root dependence on the primary stimulus amplitudes when the two primary amplitudes are varied proportionally. When one primary amplitude is held fixed, the calculated CDT-amplitude goes through a maximum when the other primary amplitude is increased—again as observed experimentally. In the model, this noteworthy amplitude behavior is a direct consequence of the cube-root dependence of the membrane velocity on pressure for large pressures which has an amplitude limiting action on the generation of the CDT. The basic properties of the CDT, as primary amplitudes and frequencies are varied, can be approximated by assuming that the 2f1−22 distortion component is generated predominantly at one place (near the characteristic place for f2).

Subject Classification: 65.26, 65.56.
Monaural detection with contralateral cue (MDCC). VI. Adding noise to the cue
Authors: Taylor M. M. , Smith S. M.
Published: October 2005

Intense cues detract from performance in the monaural detection with contralateral cue (MDCC) situation. The addition of noise to the cue, so as to partially mask the cue, restores this performance and at the same time makes the intense cue sound softer. The performance level with the masked cue is roughly the same as that of the equally loud unmasked cue, but the phase effects are the same as those of the equally intense unmasked cue. The phase relations of binaural signals appear to be related to intensity, whereas loudness is probably a more central effect.

Subject Classification: 65.50, 65.58, 65.62, 65.75.
Is the effort dependence of speech loudness explicable on the basis of acoustical cues?
Authors: Glave R. D. , Rietveld A. C. M.
Published: October 2005

Effort-dependent speech loudness (of sustained vowels) was investigated with the general intention of making a comparison between experimental loudness data and calculated loudness data (based on the Zwicker model). The adjustment method was used in the listening experiment as an alternative to the magnitude-estimation technique used in earlier experiments. The stimuli varied with respect to (1) vocal effort, (2) vowel quality, and (3) initial structure. Intensity, fundamental frequency, and duration were held constant. The speech stimuli, produced by five male speakers, were presented to 25 listeners. The equal loudness data of the listeners indicate that the speech loudness varies significantly with effort and vowel quality, while the initial structure does not have any significant influence. In the second part of the investigation, loudness was calculated on the basis of spectral information. The calculated loudness data were compared with the listener loudness data (phon level). With respect to the relative level, listener loudness and calculated loudness agree to a very large extent in effort-dependent loudness differences and loudness differences dependent on vowel quality. With respect to absolute loudness levels, the listener loudness and the calculated loudness differ almost constantly (by 9 phons). The comparative loudness data suggest that effort-dependent speech loudness changes are due to pure spectral changes, and that a special perceptual mechanism in the loudness perception of speech is questionable.

Subject Classification; 70.30, 70.20.
Attenuation of low-frequency sound in a turbulent duct
Authors: Takaku I. , Horiuchi T.
Published: October 2005

Experimantal evidence that low-frequency sound up to 2 kHz attenuates after propagation through a turbulent field is described. A wave packet of duration 2 msec is passed through a turbulent jet of air flowing perpendicular to the incident wave. The attenuation constant is proportional to the jet velocity and the dependence of the attenuation on the frequency of the incident wave is measured. The result is compared with a phenomenological analysis in terms of an equivalent turbulent friction drag and a modification of the analysis is proposed.

Subject Classification: 28.60.
Surface wave modes on elastic cylinders
Authors: Frisk G. V. , Dickey J. W. , Überall H.
Published: October 2005

Various surface wave modes may exist on solid elastic cylinders imbedded in a fluid. They fall into two classes, having velocities close to either the wave speed in the fluid (Stoneley- and Franz-type modes), or to the bulk wave speeds in the solid (Rayleigh- and Whispering Gallery-type modes). Using analytic and numerical methods, we present here a discussion of the modes of the first class, as well as of the Rayleigh mode. In the limit of infinite cylinder radius, the wavenumbers of the Rayleigh and Stoneley modes tend towards those of the Rayleigh and Stoneley waves on a flat elastic half-space, while the Franz-mode wavenumbers tend towards the wavenumber of sound in the ambient fluid. The sheet structure of the elastic surface waves is discussed in an appendix.

Subject Classification: 35.54; 40.26;30.50;20.35.
Ultrasonic parameters of freshly frozen dog tibia
Authors: Adler Laszlo , Cook K. V.
Published: October 2005

Some experiments using ultrasonic wave propagation in freshly frozen dog tibia are reported. Longitudinal velocity measurements indicate significant directional variations. Absorption measurements resulted in a linear relationship between absorption coefficient and frequency. Shear velocity has also been measured in bones.

Subject Classification: 80.20.
Growth of pea roots exposed to pulsed ultrasound
Authors: Child Sally Z. , Carstensen Edwin L. , Miller Morton W.
Published: October 2005

Studies of the growth of pea roots after exposure to pulsed ultrasound (2.3 MHz, 10 W/cm2 peak intensity) support the postulate that a cavitation-like mechanism may be responsible in part for a decrease in the growth rate. There is a significant, although reduced, effect on growth at pulse lengths as short as 3 μsec; this observation suggests that two nonthermal mechanisms may be involved.

Subject Classification: 80.40;+35.75.
Variational method and nonlinear oscillation of bubbles
Authors: Hsieh Din-Yu
Published: October 2005

A new technique, i.e., the variational method, is introduced to solve the problem of nonlinear oscillation of a spherical gas bubble in liquid. The method is simple in concept and straight-forward in application. In a sinusoidal pressure field, it is shown that besides the fundamental response, harmonic oscillations of the bubble of order 2 and 3, and subharmonic responses of order 1/2 and 1/3 can also be generated. For illustration, the subharmonic response of order 1/2 is analyzed in detail. The amplitude and phase responses as well as the threshold pressures are explicitly exhibited for one branch of the solution. The existence of another complementary branch of solution is also indicated. Stability of the solution is finally discussed also from the variational approach.

Subject Classification: 30.60, 30.75.
Analysis technique for classifying wind- and ship-generated noise characteristics
Authors: Perrone Anthony J. , King Louis A.
Published: October 2005

An analysis technique is described that permits the classification of ambient noise sources (wind generated and shipping) without the need for information concerning the environment or shipping in the area of interest. Wind-generated and ship-generated ambient noise, or a combination of the two, can be classified by finding the zero-axis crossing time of the autocorrelation function versus frequency of the long-term (greater than two weeks) ambient noise time series for a given geographic area. Results obtained from the zero-axis crossing times of the autocorrelation function of ambient noise level versus time (measured by omnidirectional hydrophones and processed through 1/3-octave filters) are bounded by two distinct zero-axis crossing times. Analysis of data from four widely separated geographic areas produces the same bounds, which suggests that they may be independent of area. In the region of the spectra where 1/3-octave bands were highly correlated with wind speed, the decorrelation time (i.e., zero-axis crossing) was found to range from 26 to 40 h. In the region of the spectra that was not wind correlated and, therefore, attributed to ship-traffic noise, the decorrelation time was found to range from 4 to 8 h. For spectra that were composites of both noise sources, the decorrelation time ranged between 8 and 26 h. The observed correlation functions were fitted to a two-term equation to aid in determining the decorrelation times for all values of the wind-generated to ship-generated noise-level ratios. Each term of the equation (one being wind related and the other ship related) is a sinusoid whose decay parameter is equal to its corresponding mean value decorrelation time and whose sinusoidal period is four times that value.

Subject Classification: 30.70, 30.80.
Multiple scattering by two cylinders
Authors: Young J. W. , Bertrand J. C.
Published: October 2005

Theoretical calculations and experimental measurements of the backscattering of a plane acoustic wave by two parallel, rigid cylinders are presented. The effects of multiple scattering between cylinders are included in the calculations. Two methods of solution of the equations are discussed. Good agreement is found between theory and experiment. Multiple-scattering calculations show the influence of the shadow of one cylinder upon the other. Variations in level of the interference peaks are correctly predicted.

Subject Classification: 30.30, 30.40; 20.30, 20.15.
Perception of voicing in English affricates and fricatives
Authors: Cole Ronald A. , Cooper William E.
Published: October 2005

Two series of experiments were conducted to study the effects of consonant and vowel duration on the perception of the voiced–voiceless distinction for the English affricates [?] vs [?] and the fricatives [v] vs [f] and [z] vs [s]. The voiceless members of each pair of speech sounds were recorded by a male speaker in a CV environment with the vowel [a] ([?a], [fa}, and [sa]) and then duplicated a number of times. The frication of each syllable was then shortened in small steps by removing frication from just prior to the vowel and then closing the gap. Additional series were constructed by shortening the vowel duration of these syllables, and the resulting series were presented to listeners in randomized sequences for identification. The results of the first series of experiments showed that shortening the duration of frication for a voiceless affricate or fricative produced a change in the percept from voiceless to voiced (i.e., from [?a] to [?a], from [fa] to [va], and from [sa] to [za]). Whereas shortening the duration of frication produced a marked shift in the percept from voiceless to voiced, shortening the duration of the vowel produced only a weak effect, and the interaction between the two shortening effects was small. The small effect of vowel duration on perception of voicing for syllable-initial affricates and fricatives was contrasted with the strong effects of vowel duration on voicing for fricatives in syllable-final position observed in prior work, and this contrast was accounted for in terms of the perceptual processing required for CVC syllables in normal listening. In the second series of experiments, the frication of [sa] was shortened to produce a series of syllables ranging from [sa] to [za] to [-a]. In selective adaptation tests, repeated presentation of these three syllables resulted in shifts in the listeners’ phonetic boundaries. Results of the selective adaptation experiment were compared to results of prior work using stop consonants.

Subject Classification: 70.30, 70.70.
Characteristics of high-frequency sea reverberation and their application to turbulence measurement
Authors: Rasmussen R. A. , Head N. E.
Published: October 2005

By using both continuous and pulsed insonification of a fixed volume at 160 kHz, measurements of scattering strength, scatterer target strengths, and reverberation spectra were made at a single location near San Diego at depths up to 90 m. Scattering strength and density of scatterers decrease slightly with depth while the short-term fluctuation increases somewhat. Dimensions of the scatterers are estimated to be of the order of millimeters. The scatterers apparently do not migrate vertically over a 24-hour period and reverberation spectra indicate that they are nonmoving or very slowly moving obstacles carried along with the current. Application of the apparatus in the detection and measurement of turbulence at considerable ranges is considered, and analyses indicate that turbulent speeds of the order of centimeters per second might be observed at ranges of approximately 100 m with a transmitted power of a few hundred watts.

Subject Classification: [43]30.40; [43]80.20; [43]28.60.
Sonic cameras
Authors: Jones C. H. , Gilmour G. A.
Published: October 2005

Westinghouse is developing two different types of sonic cameras for real time imaging in turbid water. A 2-MHz side-look sonic camera has been built for viewing the ocean bottom at angles from 35° to 55°. The plane of the bottom is mapped into an image plane behind the lens. Ninety-eight line transducers are used in the image plane to form 98 simultaneous beams. Range resolution is determined by time, as in a side-look sonar, and angular resolution is determined by the lens. A 25-cm lens obtains resolutions of 1.5 to 6 cm at ranges from 3 to 12 m. A circular-scan camera has been built to operate at 3 MHz. This camera maps a plane orthogonal to the direction of view into the image plane behind the sonic lens. The image is swept out by a row of 128 transducers rotating in the image plane. A 27-cm lens makes it possible to achieve resolutions of 1 to 3 cm at ranges from 3 to 9 m. Lens data applicable to both cameras is given and initial pictures taken with both types of cameras are shown.

Subject Classification: [43]35.80; [43]30.80; [43]35.65.
Simple frequency expression for the in-plane vibration of thick circular rings
Authors: Kirkhope J.
Published: October 2005

A simple frequency equation is derived for the in-plane vibration of thick rings, taking account of the effects of transverse shear and rotatory inertia. The remarkable accuracy of the expression is demonstrated by comparison with experimental data.

Subject Classification: [43]40.26.
Effect of activating signal bandwidth on acoustic-reflex thresholds
Authors: Popelka Gerald R. , Margolis Robert H. , Wiley Terry L.
Published: October 2005

Acoustic-reflex thresholds were determined as a function of activating-signal bandwidth in ten subjects with normal hearing sensitivity and eight subjects with noise-induced sensorineural hearing loss. Results from the normal-hearing group indicated that reflex thresholds decreased in a curvilinear fashion as a function of signal bandwidth in log frequency. Sensorineural hearing loss altered the functions by elevating reflex thresholds for signals in which the spectral content of the activating signal corresponded to the frequency region of the hearing loss. A method was proposed in which reflex thresholds for various tonal and bandlimited signals were used for predicting hearing sensitivity by frequency region.

Subject Classification: [43]65.24, [43]65.22, [43]65.75.
Intensity perception. V. Effect of payoff matrix on absolute identification
Authors: Lippmann R. P. , Braida L. D. , Durlach N. I.
Published: October 2005

In previous work (e.g., Durlach and Braida, 1969; Braida and Durlach, 1972), we have implicitly assumed that sensitivity in absolute identification of sound intensity is independent of the payoff matrix. There are a number of reasons, however, to question the validity of this assumption. For example, if the payoff matrix causes the subject to focus his attention on a particular subrange of stimuli at the expense of the remaining stimuli, the sensitivity between pairs of stimuli in this subrange might be increased relative to the sensitivity between pairs of stimuli outside this range. This paper reports the results of a series of experiments designed to test the above-mentioned assumption. On the whole, the results are consistent with this assumption. The only significant exception is that, for one of the five subjects tested, the total sensitivity varies with the payoff matrix (in a manner that appears unrelated to the specific properties of the payoff matrix). Also, the observed changes in response bias associated with the changes in payoff matrix are generally in the same direction as, but somewhat smaller than, the changes in bias that would occur in an optimal Bayes receiver.

Subject Classification; [43]65.75, [43]65.50.
Scattering of a Rayleigh wave by the edge of a thin surface layer of negligible inertia
Authors: Simons Donald A.
Published: October 2005

The problem of the scattering of a Rayleigh wave by the edge of a thin surface layer of negligible inertia is solved by means of Fourier transforms and the Wiener–Hopf technique. The effect of the layer is approximated by a pair of boundary conditions applied at the surface of the half space. The condition that the traction on the edge of the layer vanish is explicitly enforced. Expressions are given for amplitudes of the transmitted and reflected surface waves, and the power transmission and reflection coefficients are evaluated.

Subject Classification: [43]20.15, [43]20.30, [43]35.54.
Pinna disparity processing: A case of mistaken identity?
Authors: Hebrank J. H.
Published: October 2005

Searle et al. [J. Acoust. Soc. Am. 57, 448–455 (1975)] conclude that disparities between right and left pinna filtering are used as median-plane localization cues. Their experiments fail to separate elevation cues due to pinna disparities from elevation cues due to binaural IAD and ITD information caused by slight misalignment of subjects’ heads with the median plane defined by the sound source.

Subject Classification: [43]65.62, [43]65.20.
Localized cochlear microphonics recorded from the spiral lamina
Authors: Yates Graeme K. , Johnstone Brian M.
Published: October 2005

A greatly improved localization of the cochlear microphonic (CM) recording is obtained by the technique described in this report. CM tuning curves are obtained from the spiral lamina, immediately adjacent to the basilar membrane, when the first turn of the cochlear scala tympani is opened and drained. High-frequency slopes of −85 to −110 dB/octave are recorded, compared with the best slopes of only −30 dB/octave recorded by the differential electrode technique, and the tuning curves closely resemble published mechanical tuning curves for the basilar membrane. The technique should aid considerably the study of CM generator mechanisms.

Subject Classification: [43]65.20, [43]65.40.
Time coherence of acoustic signals transmitted over resolved paths in the deep ocean
Authors: Williams R. E. , Battestin H. F.
Published: October 2005

Long-term coherence measurements have been made of the stability of broad-band acoustic signals transmitted on single paths through the deep ocean over distances of 145, 250, 495, and 635 NM. The stability of individual ray paths was measured by separating the arrivals in time and angle. Twenty-nine acoustic phase records with durations from 5 to 32 h were analyzed. Typical coherence intervals of 2 to 8 min were found in which the phase of the cross-correlation of the received signal with a replica varied by no more than ±π/2 rad (±0.6 msec) at 400 Hz. Coherent intervals of 8- to 12-min duration at 400 Hz were common, while occasional long periods on the order of 20 min could be found. The spectra of these phase records possess a dominant low-frequency peak overlapping the 12- and 24-h tidal frequencies, but also show much weaker peaks at periods of 1 1/2, 3, and 5 h. The latter could be caused by internal waves, nonlinear overtides, or atmospheric pressure variations. No other effects of the moving ocean surface or of higher-frequency internal ocean instabilities were found.

Subject Classification; [43]30.20; [43]60.30; [43]30.82; [43]60.20.
Cavitation inception thresholds in water and nuclei spectra by light-scattering technique
Authors: Yilmaz E. , Hammitt F. G. , Keller A.
Published: October 2005

Cavitation inception thresholds in water are measured and correlated with nuclei spectra, measured by the laser-light-scattering technique. The effects of temperature, settling time, total air content, various impurity particle additions, and polymer addition are examined and compared with theoretical predictions.

Subject Classification: [43]30.60, [43]30.70; [43]35.65; [43]25.60.
Technique for measuring the adiabatic compressibility, density, and sound speed of submicroliter liquid samples
Authors: Apfel Robert E.
Published: October 2005

An acoustical technique for measuring a known function of the adiabatic compressibility and density of a very small liquid sample (4×10−6 −4×10−3 ml) has been developed. The technique involves a comparison of the conditions required for the acoustic levitation of the sample at a given position in a known, immiscible ’’host’’ liquid and the levitation of a reference droplet of known properties at the same position. Since the success of this technique depends on the predictions of the theory for the ’’Acoustic Radiation Pressure on a Compressible Sphere’’ [K. Yosioka and Y. Kawasima, Acustica 5, 167–173 (1955)] as applied to instances when buoyancy and acoustic forces balance, it was decided to test the validity of the procedure by using liquids of known properties so that a comparison with our results would be possible. Using the known density ρ, the experiment plus theory allows us to calculate the adiabatic compressibility βs and the sound speed = (1/ρβs)1/2. Results for the sound speed of a number of common organic liquids (n-pentane, benzene, n-hexane, O-xylene, and toluene) are within 2% of the results of traditional measurements. Two particularly attractive features of this procedure are that (1) the results are independent of droplet size and (2) the parameters of the sound field need not be known. This technique should be directly applicable to measurements of properties of superheated and supercooled liquids.

Subject Classification: [43]35.24.
Transmission of sound through sandwich panels: A reconsideration
Authors: Dym Clive L. , Ventres C. Samuel , Lang Mark A.
Published: October 2005

A reconsideration of a previous study of the transmission loss of sandwich panels is presented. An erroneous calculation of the transmission loss is corrected, and new results are presented. Also, some interesting implications for the design of walls of high transmission loss are pointed out.

Subject Classification: [43]55.75.
An approximate bivariate density function for orthogonal filtered Poisson processes with applications to volume reverberation problems
Authors: Ehrenberg John E.
Published: October 2005

A bivariate density function approximation for orthogonal filtered Poisson processes is derived. The approximation has the proper impulsive behavior at the origin. This is a significant improvement over the Edgeworth series approach used previously to obtain the first-order density approximation of this type of process. The bivariate density function approximation is used to evaluate expressions for the level crossing rate of a reverberation process and the probability of false alarm for an active sonar operating in a reverberation-limited environment. The accuracy of the level crossing rate expression is investigated using a Monte Carlo simulation.

Subject Classification: [43]60.20; [43]30.40.
Propagation in an inversion and reflections at the ground
Authors: Embleton T. F. W. , Thiessen G. J. , Piercy J. E.
Published: October 2005

The propagation of sound is considered for an atmosphere in which the sound velocity increases linearly with height. For source and receiver separation large compared with their heights above the ground, there are in general four possible ray paths between source and receiver having a given number of ground reflections n≳1. For n=0, i.e., no reflections, there is one ray path; and for n=1 there are three possible ray paths. By suitable grouping of the ray paths it is possible to evaluate the effects of reflection at a ground of known, finite impedance (especially near the source), assuming coherence between neighboring rays; and also to evaluate the net sound intensity of waves traveling via more widely separated paths in the normally turbulent atmosphere assuming incoherence. A temperature inversion is found, using ray theory, to increase the sound level at large horizontal distances inside the shadow region due to finite surface impedance, that is otherwise predicted by wave theory for a neutral atmosphere.

Subject Classification: [43]28.40; [43]20.20, [43]20.30.
Recognition masking of auditory lateralization and pitch judgments
Authors: Massaro Dominic W. , Cohen Michael M. , Idson Wendy L.
Published: October 2005

Two experiments determined backward and forward recognition masking functions in a lateralization task. Observers were presented with a 20-msec pure tone that differed in intensity to the two ears. The task was to indicate whether the tone came from the right or left. A second backward-masking tone interfered with the lateralization of the first test tone if it was presented within 180–250 msec of the first tone presentation. In contrast, a forward-masking tone had to be presented within 80 msec of the test-tone presentation in order to interfere with lateralization of the test tone. The results also showed that observers tended to lateralize the test sound in the direction of the masking sound if the test and masking sounds occurred within a 100-msec period. In a third experiment, subjects were required to identify a test tone as high or low in pitch in a recognition masking task. Although pitch judgments showed as much or more backward masking than lateralization judgments, significantly less forward masking was found in the pitch judgment task. Relative to lateralization judgments, observers showed a smaller tendency to judge the pitch of the test tone in the direction of the pitch of the masking sound.

Subject Classification: [43]65.75, [43]65.54, [43]65.62, [43]65.58.
Effect of interrupting recovery on loss in cochlear microphonic sensitivity
Authors: Price G. Richard
Published: October 2005

A previous experiment [G. R. Price, J. Acoust. Soc. Am. 56, 183–189 (1974)] produced data that documented an early recovery process (ERP) measurable in the cochlear microphonic (CM) following intense stimulation. At that time, a hypothesis was advanced that if the ERP were interrupted by successive stimuli during intense intermittent stimulation, unusually large losses would result. The present experiment tested this hypothesis by comparing loss in CM sensitivity in the ears of anesthetized cats following one of three exposure conditions: (1) intermittent stimulation timed to interrupt the ERP (1 min on, variable off time), (2) the same amount of stimulation with a maximum of recovery time (1 min on, 9 min off), (3) and continuous stimulation. All ears received 30 min of stimulation with a 5.0-kHz tone at 30 dB above that intensity necessary to produce a maximum in CM output. Interrupting the ERP when 5 dB from completion resulted in 1.2 dB/min of loss, while allowing it to run to completion produced losses of only 0.6 dB/min. Continuous stimulation resulted in 0.9 dB/min of loss. The data supported the hypothesis and demonstrated the importance of the ERP. The implications of these findings for the problem of hearing loss to intermittent stimulation are discussed.

Subject Classification: [43]65.66, [43]65.40.
Absolute measurement of acoustic particle velocity
Authors: Taylor K. J.
Published: October 2005

A method for the absolute measurement of acoustic particle velocity is described. The technique uses the Doppler shift in frequency of laser light scattered from small particles suspended in the medium and vibrating with sensibly the same amplitude as the surrounding molecules. The measurement is made over a small volume at the intersection of two focused laser beams and since no transducer is required the sound field is not disturbed. Some typical data are presented illustrating its use over the range of particle velocities 0.5–50 mm sec−1 rms and it is shown that the results should be reliable at frequencies up to 50 kHz in air and higher frequencies in more dense media.

Subject Classification: [43]85.22; [43]35.65.
Covariance between Fourier coefficients representing the time waveforms observed from an array of sensors
Authors: Hodgkiss W. S. , Nolte L. W.
Published: October 2005

Typically, the assumption of a long observation interval is made to achieve uncorrelatedness between Fourier coefficients at different frequency indicies. An explicit relationship between observation interval length and covariance between the Fourier coefficients is obtained to provide insight as to how long the observation interval should be to approximate this desirable condition.

Subject Classification: [43]60.20.
Compound action potential (AP) tuning curves
Authors: Dallos Peter , Cheatham Mary Ann
Published: October 2005

With a tone-on-tone masking procedure the compound action potential (AP), elicited by brief tone bursts of set frequency and intensity, was decreased by a constant fraction. The frequency–intensity pairs formed by the masker that yield this decrease generate the AP tuning curve. It is demonstrated that such tuning curves are very similar to both psychophysical tuning curves and single VIIIth-nerve-fiber tuning curves. Changes in the properties of these curves are described as functions of stimulus frequency and level, mode of masking (simultaneous and forward), and parameters of the masker.

Subject Classification: [43]65.40, [43]65.42, [43]65.58.
Sound attenuation as a function of depth in the sea floor
Authors: Hamilton Edwin L.
Published: October 2005

Recently published data on the attenuation of compressional (sound) waves in marine sediments and sedimentary rocks as a function of frequency and sediment porosity have been added to previously published figures. The revised figure illustrating attenuation as a function of frequency (5 Hz–1 MHz), and attendant discussion, continue to support the conclusion that attenuation is approximately related to the first power of frequency in sands, muds, and sedimentary rocks. The revised figure illustrating sediment porosity versus attenuation affirms that sediment porosity is an important index property which can be used to predict sound attenuation in surficial sediments. Data were collected and illustrated on sound attenuation as a function of depth in the sea floor. It is concluded that attenuation decreases with about the −1/6 power of depth in sands. As a silt–clay sediment (mud), or turbidite, is placed under increasing overburden pressure, there may be a progressive increase in attenuation due to reduction in sediment porosity, and a progressive decrease in attenuation due to increasing pressure on the sediment mineral frame. At about 200-m depth a null point may be reached. Thereafter, pressure is the dominant effect, and attenuation decreases smoothly with depth and overburden pressure. The figure can be used to aid prediction of sound attenuation in sediment and rock layers in the sea floor.

Subject Classification: [43]30.20.
Lateralization at high frequencies based on interaural time differences
Authors: McFadden Dennis , Pasanen Edward G.
Published: October 2005

Sensitivity to interaural time differences at high frequencies is demonstrated in a number of experiments. Two types of waveforms are used—bands of noise and two-tone complexes. Variables studied are rate and depth of fluctuation of the envelope, overall intensity, and additivity of interaural time information across frequency regions. In many conditions of listening, sensitivity to interaural time differences at high frequencies compares favorably with sensitivity at low frequencies—good performace requires only tens of microseconds of interaural time delay.

Subject Classification: [43]65.62, [43]65.68.
Asymptotic theory of scattering by a rough surface progressing over an inhomogeneous ocean
Authors: Labianca F. M. , Harper E. Y.
Published: October 2005

A general asymptotic theory of scattering by a moving rough surface is presented. The theory is valid for a slowly varying refractive index, and for ocean-surface wave heights that are small compared with the acoustic wavelength and the ocean-surface correlation length. In contrast with the Kirchhoff or physical optics approximation, this theory is valid when the acoustic wavelength and ocean-surface correlation length are of the same order. The ocean surface is described as a sum of gravity waves of varying frequency progressing in different directions. It is demonstrated that, to a given order of approximation in the asymptotic theory, the average energy associated with signal sideband rays is precisely accounted for by a reduction of intensity of the reflected carrier. Wave number diagrams are introduced which are extremely useful for depicting the directions of the incident and scatteres rays at the surface, demonstrating the effect of varying surface-wave and acoustic frequency, and demonstrating the frequency cutoff of the sideband power spectrum. The phenomenon of Bragg resonance at glancing incidence of the carrier is also easily depicted. The theory can accomodate the effects of ray focusing, both in the carrier and sidebands, through the use of uniformly valid asymptotic expansions which account for the presence of caustics.

Subject Classification: [43]30.40, [43]30.20, [43]30.25, [43]30.30.