bluuebunny/crossref_metadata_2025 huggingface dataset:
Radiation of sound from a small loudspeaker located in a circular baffle
Authors: Lauchle Gerald C.
Published: October 2005

The exact theory for the radiation of a small loudspeaker in the surface of a rigid circular disk of elliptic profile is presented. Numerical results are included for a monopole at the center of the disk and on its surface. The solution for the loudspeaker in the center of a free circular baffle is then formulated by superimposing the solution of a positive source on one side of the baffle with that for a negative source on the other side. For wavelengths greater than the circumference of the baffle, the resulting field turns out to be very similar to that of a dipole of finite dipole axis. However, for wavelengths smaller than the diameter of the baffle, the diffraction field is shown to be dominated by edge effects. In particular, the total field may also be represented by a simple ring−point source combination, i.e., the edge of the baffle is essentially replaced by a ring source. It is shown that in the vicinity of the axis of the baffle, the shape of the frequency response curve depends little on how much volume flow is generated on the opposite side of the baffle. In other words, it makes little difference (except in absolute level) whether a loudspeaker is enclosed in a box or is permitted to radiate from the rear.

Subject Classification: 20.15, 20.30, 20.55.
Acoustic reflection and transmission characteristics for thin plates
Authors: Barnard G. R. , Bardin J. L. , Whiteley J. W.
Published: October 2005

A method for determining the acoustic properties of thin plates is described. Existing theoretical expressions are used to calculate transmission and reflection coefficients for sound waves striking the plates at arbitrary angles of incidence. Theory is substantiated by experimental data, and refined values for absorption coefficient and shear velocity are obtained by combining theory and experiment. Materials tested were Absonic−A, plexiglass, and polyethylene.

Subject Classification: 30.30, 30.50, 20.30.
Nonlinear electroelastic equations cubic in the small field variables
Authors: Tiersten H. F.
Published: October 2005

The nonlinear differential equations and boundary conditions containing terms up to cubic in the small field variables are obtained from general rotationally invariant nonlinear electroelastic equations derived previously. The electroelastic equations cubic in the small field variables are considerably more tractable than the general electroelastic equations and are applicable in the description of such phenomena as the dependence of wave velocities on wave amplitudes and resonant frequencies on vibration amplitudes in addition to a host of other nonlinear phenomena. The nonlinear constitutive equations for an isotropic purely elastic solid containing terms up to cubic in the small mechanical displacement gradients are presented. The nonlinear equations for the extensional motion of thin isotropic plates containing terms up to cubic in the small mechanical displacement gradients in the plane of the plate are obtained and the influence of the vertical inertia is included, in addition to the extensional stiffness and inertia, when the plating is attached to an electroelastic solid.

Subject Classification: 40.24.
Dichotic masking of consonants by vowels
Authors: Repp Bruno H.
Published: October 2005

The dichotic masking effects of a vowel (/a/) on CV syllables (stop + /a/) were investigated by comparing the effect of CV masks with (a) the effect of CV masks in which the vowel was shortened and (b) the effect of an isolated vowel mask. The vowel exerted a clear masking effect, both when isolated and when in CV context, but this effect was much less pronounced than the ’’masking’’ produced by a competing consonant. It was hypothesized that consonants exert their ’’masking’’ effect on consonant (CV) targets at a central (phonetic) level, while vowel masking is largely a ’’peripheral’’ (auditory) phenomenon. Detailed analysis of the vowel masking effect revealed several distinct components. The two most interesting effects were (a) a relationship between stimulus onset asynchrony and the probability of voiced responses, which was interpreted as masking and substitution of the cue of voice onset time, and (b) a relationship between the pitch contour of the vowel mask and the probability of a voiced response, which suggested that the pitch contour of an isolated vowel may act as a voicing cue when paired with a consonant in the other ear. While all these effects were interpreted as consequences of relatively peripheral binaural mixing, the possibility that part of the vowel masking effect occurred at a later, phonetic processing stage could not be excluded.

Subject Classification: 70.30.
Normal modes in vocal cord tissues
Authors: Titze Ingo R. , Strong William J.
Published: October 2005

The human vocal cord is treated as an elastic material capable of propagating compressional, shear, and surface waves. A mathematical formulation for commonly observed vibrational modes is developed. This includes horizontal as well as vertical tissue displacements. Current vocal cord models are discussed and evaluated in terms of their ability to describe adequately the vibrational degrees of freedom of the cords.

Subject Classification: 70.20.
Sound production in the tsetse fly G
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Authors: Erickson I. E. Carina , Mo/ller Aage R.
Published: October 2005

Sound production in the tsetse fly, Glossina morsitans, was studied in the frequency range from 0.5 to 100 kHz. It was found that the sound has an ultrasonic component and that this component is related to the behavior of the fly. There is a consistent difference between mating and feeding sounds in the spectrum above 15 kHz. There is also a consistent difference between the sounds produced by males and females in that the former rarely produce sounds with significant energy above 15 kHz.

Subject Classification: 80.50, 80.60.
Three-dimensional acoustic wave scattering and diffraction by an open-ended vertical soft cylinder in a half-space
Authors: Teng Y. C. , Kuo J. T. , Gong C.
Published: October 2005

The formal solutions to the three-dimensional problem of scattering and diffraction due to an impulsive acoustic point source in a fluid half-space, in which a semiinfinite vertical soft cylinder is embedded, have been obtained in integral forms. The early time-displacement velocities have been evaluated (1) in the shadow region by the Residue–Cagniard method and (2) in the illuminated region by the saddle-point–Cagniard method. In the shadow region, there are two types of diffracted waves, i.e., the diffracted waves without and the diffracted waves with the reflection from the free surface. In the illuminated region, there are four types of waves: the direct wave, the reflected wave from the free surface, the reflected wave from the cylinder without reflection from the free surface, and the reflected wave from the cylinder with reflection from the free surface. Numerical results for the early time displacement velocities in the shadow region and in the illuminated region for the cases r = a, z = 5a, ϑ − ϑ0 = 0°, 90°, 120°, 150°, and 180°, and r0 = 5a, z0 = 10a are given.

Subject Classification: 20.30, 20.15.
New evidence of the mechanisms of noise generation and radiation of a subsonic jet
Authors: Maestrello Lucio , Pao S. Paul
Published: October 2005

Measurements of sound-pressure gradient near a subsonic jet have shown that coherent sound is emanated from the flow in the form of narrow beams. This conclusion is drawn from a large data base using correlation techniques, and it is further confirmed by additional experiments.

Subject Classification: 28.65; 50.55.
Some accoustical characteristics of a crossing-jet noise source
Authors: Vér István L.
Published: October 2005

The acoustical characteristics of a high-intensity omnidirectional sound source used in acoustical scale-model experiments are described in this paper.

Subject Classification: 50.30; 55.10.
Reverberation time of the Rotunda of Thessaloniki
Authors: Tzekakis Emmanuel G.
Published: October 2005

The Rotunda of Thessaloniki is a unique 4th century monument of romanesque art, with an octagonal floor plan and a volume of 15 645 n3. Today it is used as a hall for orchestral and choral presentations. The reverberation time of the Rotunda has been measured on three different occasions, and the obtained data, together with the listeners absorption calculations, are presented. Further, the hall’s total absorption is given and the problem of the higher than expected absorption values is shortly discussed.

Subject Classification: 55.45.
Normal-mode theory of underwater sound propagation from stationary multipole sources: results for a realistic sound-speed profile
Authors: Haug Anton J. , Graves Ronald D. , Überall H.
Published: October 2005

A normal-mode approach that solves the wave equation governing underwater sound propagation from a point source with directivity expressible as an expansion in spherical multipoles is summarized. The theory is extended by the development of a general theory of propagation loss for multipole sources of arbitrary order. Exact long-range pressure field and propagation loss expressions are developed and presented for the first three multipole orders. Numerical results of the pressure fields and the propagation loss for monopole, dipole, and quadrupole sources are presented for the case of a realistic sound-speed profile.

Subject Classification: 30.20; 20.15, 20.40.
Pulse-echo method of investigating the properties of mechanical resonators
Authors: Bell J. F. W. , Johnson A. C. , Sharp J. C. K.
Published: October 2005

Vibrational sensors can be designed in such a way that the frequency of one of their modes of vibration is a function of temperature, pressure, density, or other parameter, making them the basis of various instrumentation transducers. These can be driven remotely by means of a line carrying bursts of plane waves of stress analogous to sonar or radar. The simple analysis of such a system, where only one mode at a time is considered, is unsatisfactory, and a complete general theory has been developed. This applies to an extended object with an arbitrary pattern of resonant frequencies, internal energy losses, and mechanical couplings to the line. The basic Navier–Stokes equation of motion was solved for this boundary-value problem to give a pole-zero diagram for the system. Computer programs were used to invert the function into the time domain and plot the echo-return traces. The theory has been used to relate experimental observations of the spectra of isotropic disks of a variety of materials to recent theoretical studies. Accurate values of elastic constants and their temperature coefficients have been obtained. The special case of a line resonator, which has a harmonic spectrum, enables the internal friction losses to be evaluated absolutely. To make an automatic system where the drive frequency follows the resonant frequency, a number of control signals are possible. A computer program was prepared to determine the parameters of the various phase control loops available.

Subject Classification: 40.24.
Identification of structural parameters using low-amplitude impulsive loading
Authors: Sweet Arnold L. , Schiff Anshel J. , Kelley John W.
Published: October 2005

A parameter-estimation procedure is developed using the average of the response of a structure to a sequence of impulsive force loadings. The finite Fourier sine and cosine transforms of the averaged response are computed. using a mathematical model of a linear one-degree-of-freedom system, whose acceleration response has normal uncorrelated noise added to it, the joint probability density function of the Fourier coefficients is found. Applying the principle of maximum likelihood, estimates for the percent of critical damping, the natural frequency, and the magnitude of the impulse are computed using Marquardt’s method. Data were generated by digital simulation, analog simulation, and by exciting an experimental model. The resulting estimates and their confidence intervals are shown in tabular form. Error analysis due to random impulsive forces, finite pulse width of the force loading, and correlation of the noise are performed. The technique can be used in estimating the damping of systems in which the response to impulsive loading can be measured but is small relative to the ambient response.

Subject Classification: 45.40; 40.35.
Effects of flanking and test environment on lab–field correlations of airborne sound insulation
Authors: Jones Robert E.
Published: October 2005

Previous attempts to correlate lab and field sound-insulation performance have been based on a comparison of the lab sound-transmission class (STC) and the field sound-transmission class (FSTC). In this study comparisons of the 1/3-octave-bandwidth transmission loss (TL) values are made taking into account partition transmission, flanking transmission, and test-environment factors. An experimentally determined flanking TL is obtained through a quantitative relationship between the partition, flanking, and field TL. This determination allows separation of test environment factors related to diffuseness and modal distribution from flanking transmission. Also noted under field conditions are interactions between the coincidence phenomena and the sound field under absorptive room conditions (reverberation time = 0.5 sec), demonstrating that the properties of a partition depend in part on the dwelling-unit furnishings. Because all the test-environment effects observed resulted in TL values higher than those of a properly adjusted classical lab, the conclusion is drawn that for replicate partitions field TL data may under certain conditions exceed lab TL data by as much as 5 dB when no flanking exists. Specific field TL values are likely to be lower than lab TL values owing to the accumulated effects of flanking, leaks, and assembly differences.

Subject Classification: 55.75.
Long-aperture parametric receiving arrays
Authors: McDonough R. N.
Published: October 2005

The nonlinear interaction of a strong high-frequency local sound source with a weak low-frequency sound signal can be used to construct a system (’’parametric receiving array’’) for passive reception of the signal. Analytic formulas exist which describe the behavior of such a system. In this note, we develop a design procedure using these formulas, which leads to optimal system parameters. The procedure is illustrated by the design of parametric arrays for the reception of underwater sound signals in the 25–100-Hz band. Beamwidths of the order of 15 ° seem feasible, while beamwidths as narrow as 5 ° are probably not feasible. Such an array could be deployed in water without the necessity of phasing sensors along the (necessarily long) aperture.

Subject Classification: 25.35; 30.82; 60.10.
Sound radiated by low-frequency vibrations of slender bodies
Authors: Chertock George
Published: October 2005

Simple and practical formulas are derived for computing the near or far sound-pressure field radiated by a slender body which vibrates in a low-frequency whipping mode, or a low-frequency accordion mode in water. The calculations can be made by simple quadratures, and require a specification of the modal vibration pattern along the length, the cross-section area along the length, and a mean radiation impedance coefficient which can be estimated from independent data or calculated from an explicit formula derived here. Comparison is made with several other methods used to analyze these sound-pressure fields. The analyses are specific examples of a general technique for transforming a solution for the incompressive field of a body in low-frequency vibration to a solution that is valid in the near- or farfield of an acoustic compressible medium.

Subject Classification: 20.55; 40.20.
Acoustic response in a liquid overlying a homogeneous viscoelastic half-space
Authors: Magnuson Allen H.
Published: October 2005

An analytical model is developed for use in marine sediment identification on the Continental Shelf. The effects of rigidity and internal energy dissipation are taken into account by treating the subbottom as a viscoelastic solid. The acoustic response due to a harmonic point source is computed using a Green function formalism. Expressions are given for the frequency-domain Green function for subcritical and supercritical incidence angles. The response is interpreted as the sum of direct, reflected, and refracted waves.

Subject Classification: 20.30; 20.15.
Calculation of the range-Doppler plot for a doubly spread surface-scatter channel at high Rayleigh parameters
Authors: McDonald J. F. , Tuteur F. B.
Published: October 2005

No abstract supplied.

Subject Classification: 20.15, 20.30; 28.10; 60.20.
Perturbation theory for scattering of sound from a point source by a moving rough surface in the presence of refraction
Authors: Harper E. Y. , Labianca F. M.
Published: October 2005

A general perturbation theory is presented which is valid for small surface waveheights and for acoustic wavelengths of the order of the ocean-surface correlation length. Formal solutions for the perturbed field are given and are specialized, to the second order of approximation, for the case of a random ocean surface. The scattering reduces the intensity of the carrier (source) signal and creates signal sidebands that are not in general symmetric in amplitude about the carrier. A pair of system functions for the signal sidebands is defined.

Subject Classification: 30.40, 30.30, 30.25; 20.15.
Two-channel listening to musical scales
Authors: Deutsch Diana
Published: October 2005

Ss listened to a dichotic tonal sequence consisting of the repetitive presentation of the C major scale with successive tones alternating from ear to ear. The scale was presented simultaneously in both ascending and descending form, such that when a component of the ascending scale was in one ear, a component of the descending scale was in the other, and vice versa. All Ss channeled this sequence by frequency range: no S channeled by ear of input, and none reported a full ascending or descending scale. Various illusory percepts were obtained, which varied in correlation with the handedness of the listener. Right-handers tended to perceive the upper tones of the dichotic sequence as emanating from the right earphone and the lower tones from the left, and to maintain this percept when the earphones were places in reverse position. Left-handers as a group did not display the same localization tendency.

Subject Classification: 65.22, 65.54, 65.62; 75.10.
Decision processes in frequency discrimination
Authors: Jesteadt Walt , Sims Sandra L.
Published: October 2005

The ability to discriminate a change in frequency was measured in 2IFC, same-different, and yes–no paradigms using two tasks commom in the literature—discrimination of two pure tones differing only in frequency and detection of frequency modulation (FM). In the pure-tone task, differences in the level of frequency-discrimination performance as a function of paradigm were similar to those previously observed for both frequency and intensity discrimination. The level of performance in 2IFC and same–different exceeded the level of performance in yes–no by more than the theory of signal detection would predict. For the FM detection data, differences in the level of performance between paradigms were less than the theory of signal detection would predict. These differences increased, however, when the same subjects were tested in a task requiring discrimination of two FM tones. These results suggest that a memory factor is operating in discrimination tasks to a greater degree than in detection tasks. The memory factor is interpreted in terms of criterion variance.

Subject Classification: 65.54, 65.35, 65.75.
Scattering from a sinusoid: derivation of linear equations for the field amplitudes
Authors: DeSanto John A.
Published: October 2005

The problem of constructing the scattered field for plane-wave incidence on a sinusoidal surface is considered. Above the highest excursion of the surface, the scattered field is written in the usual way as a superposition of upgoing and decaying waves. Linear equations are derived for the coefficients of these waves. Both soft and hard boundaries are considered, as well as arbitrary incidence angle. The equations for the soft boundary condition are similar to those of Uretsky, but the derivation is simpler. The full results for the hard boundary condition are apparently new.

Subject Classification: 20.30.
Nomogram for estimating noise propagation in urban areas
Authors: Lee K. P. , Davies H. G.
Published: October 2005

A nomogram, generated numerically, is presented for estimating sound levels generated by point noise sources in urban street complexes. The nomogram accounts for street width, distance of the receiver from the source, reflection coefficient of the building walls, and includes cases where the receiver is across one or more street intersections or is around a street corner from the source. The effect of ground reflection is included.

Subject Classification: 50.80; 20.20; 28.40.
Effects of diffusion on gaseous cavitation bubbles
Authors: Eller Anthony I.
Published: October 2005

Rectified diffusion is a mechanism whereby a gas bubble, set into pulsation by a sound field, grows in size because of an effective gating action by the bubble surface area. Bubbles that might otherwise dissolve will grow instead if the sound pressure amplitude exceeds a threshold that depends on the bubble size. A theory of rectified diffusion is used to determine the threshold conditions for bubble growth and to calculate the rates of growth for conditions above threshold. Implications of the results are then examined with regard to the problems of the nucleation of gaseous cavitation and the shifting size distribution of a bubble population. Although calculated thresholds for growth have been found to agree with observed thresholds, calculated growth rates are often much lower than the observed rates. Reasons for the partial failure of the theory are suggested, and recent attemps to improve the theory are indicated.

Subject Classification: 25.60.
Cavitation dynamics. I. A mathematical formulation
Authors: Flynn H. G.
Published: October 2005

A set of equations has been derived to describe the dynamical motions of small cavitation bubbles in liquids set into motion by an acoustic pressure field. The mathematical formulation takes into account heat conduction inside a bubble and in the surrounding liquid, and the viscosity, compressibility, and surface tension of the liquid. The effect of vapor pressure may be determined as a function of the interfacial temperature. The formulation consists of nonlinear ordinary differential, integral, and algebraic equations, and has been programmed for solution on a digital computer.

Subject Classification: 25.60; 35.68.
Finite-amplitude plane waves in ducts with varying properties
Authors: Nayfeh Ali Hasan
Published: October 2005

The method of multiple scales is used to determine a first-order uniform expansion for finite-amplitude plane waves of continuous waveforms propagating in a duct having a slowly varying cross section and filled with an inhomogeneous fluid. Losses due to the acoustic boundary layer or a slight wall admittance can be accounted for by decomposing the continuous waveform into its Fourier components and correcting the amplitude and phase of each component independently. Losses at shocks can be accounted for by using weak-shock theory. The results show that the shock formation distance tends to be shortened in a converging section and tends to be lengthened in a diverging section of the duct.

Subject Classification: 25.20; 20.45.
Noise radiated by internal-combustion engines
Authors: Brammer A. J. , Muster D.
Published: October 2005

The surfaces of an internal-combustion engine can be expected to radiate sound resulting from time-varying gas and mechanical forces developed during the operating cycle. The rapid pressure rise accompanying spontaneous ignition of the fuel within the combustion chamber leads to the characteristic ’’knocking’’ noise of diesel engines. In contrast, the rate of change of pressure within the cylinders of spark-ignition engines is comparatively slower, which results in less intense gas forces. Further, impacts between the piston and cylinder walls, or deformation of the crank mechanism, may be responsible for the noise of some engines. In both cases vibrational energy is radiated primarily by the crankcase and by nonstructural parts, such as the oil pan and valve covers. For air-cooled engines there is significant radiation from the cylinder-cooling fins. Engine-radiated noise may dominate the overall noise spectrum of diesel-powered trucks at speeds near 30 mph.

Subject Classification: 10.60; 50.30, 50.50.
Community noise survey of Cincinnati, Ohio
Authors: Malchaire Jacques B. , Horstman Sanford W.
Published: October 2005

In a field investigation of noise levels in Cincinnati, Ohio, 20-min noise recordings were made at 19 sites during 19 weekdays, at ten different times, according to an incomplete Latin-square statistical plan. L10, L50, and L90 values were determined for each sample. An analysis of variance was carried out separately for each of the three parameters and the significance of sampling hours and days analyzed. L10 and L90 values were found highly correlated to L50 values (r = 0.96 and 0.93). However, the L10 − L90 difference which is the basis of the Traffic Noise Index was found to be poorly correlated to L50 levels (r = 0.44).

Subject Classification: 50.70; 50.75.
Masking patterns for continuous and gated sinusoids
Authors: Leshowitz Barry , Cudahy Edward
Published: October 2005

The masking of a brief tonal signal by continuous and gated sinusoids was investigated. Masking patterns depicting the threshold of a signal of frequency fs as a function of masker frequency fm for the two masker presentations were compared. In the frequency region fm ≳ fs, the briefly presented gates masker was always a more effective masker than the continuous steady-state background, even under conditions in which energy spread of the gated masker was minimized. For fm < fs, the gated–continuous threshold shift, sometimes called the ’’overshoot,’’ reversed when a low-level background noise was added to the tonal nasker in order to mask audible combination tones. The presence of combination tones in the steady-state masker condition precluded application of a simple energy detection model in the frequency region fm < fs. An attempt to simulate the results for fm ≳ fs with an energy-detection scheme in conjunction with a detailed spectral analysis of the stimuli was also unsuccessful.

Subject Classification: 65.58, 65.50, 65.75.
Signal–noise duration, psychophysical procedure, interaural configuration, and the psychometric function
Authors: Osman Eli
Published: October 2005

Effects on locations and slopes of psychometric functions are reported for 2IFC and YN tasks as a function of the duration (particularly 10–125 msec) of synchronously gated tone bursts (400 Hz) and noise bursts (broad-band, Gaussian) under homophasic (NOSO) and antiphasic (NOSπ) listening conditions. Emphasis is placed on the finding that slopes are consistently lower at 10 msec as opposed to 125 msec for synchronously gated tone and noise, and the effect is not dependent on either psychophysical procedure or interaural configuration. Published results for continuous noise maskers suggest that such a duration dependency does not appear. Slopes do not seem to be affected by either interaural configuration, psychophysical procedure, or masker continuity condition for 125-msec signals. Large threshold increases occur at the short duration only under YN listening, and are largest for NOSπ. The nature of combined threshold and slope shifts may be incompatible with existing detection theories.

Subject Classification: 65.60, 65.58, 65.75; 50.70.
Physiological correlates of intonation patterns
Authors: Collier René
Published: October 2005

An experiment has been performed to assess to what degree laryngeal muscle activity and subglottal air pressure affect the rate of vocal cord vibration in speech. Attention has been limited to those changes in the rate of vocal cord vibration that are associated with the physiological implementation of prosodic phenomena such as intonation and prominence. Subglottal air pressure was measured directly through a catheter inserted between the cricoid and thyroid cartilages. Using hooked-wire electrodes, the electromyographic activity was recorded in the right- and left-side cricothyroid muscle and in the sternohyoid, sternothyroid, and thyrohyoid muscles. The data were collected for one subject, a native speaker of Dutch. The results of the experiment show that, in this particular speaker, (1) cricothyroid muscle activity bears the most direct relationship to all major F0 changes, in that the contraction of this muscle raises F0 while its relaxation has an F0 lowering effect: (2) subglottal air pressure controls the gradually falling base line of the F0 contour and gives support to a rapid F0 drop if it occurs on the utterance-final syllable; and (3) the sternohyoid, sternothyroid, and thyrohyoid muscles have no direct effect on F0.

Subject Classification: 70.20, 70.70.
Perceptuo-motor adaptation to speech: an analysis of bisyllabic utterances and a neural model
Authors: Cooper William E. , Nager Richard M.
Published: October 2005

After repetitive listening to a voiceless plosive contained in a consonant + vowel syllable, the voice onset time (VOT) durations of a voiceless plosive uttered in a CV environment are systematically shortened. This effect, which provided initial evidence for a common processor mediating the perception and production of speech, has been extended in this large-scale study to the case of voiceless plosives embedded in a CVCV́ environment. For the utterances [rephí] and [rethí] shortening effects were observed similar to the effects found earlier for simple CV utterances [phi] and [thi]. Although [rephí] was used as the CVCV́ adapting stimulus, the average magnitude of the perceptuo-motor effect was considerably larger for [rethí] utterances than for [rephí] utterances (6.5 msec of VOT compared with 2.7 msec of VOT). Additional acoustic measurements revealed that tow other properties of the [rethí] utterances, the vowel duration of the stressed [í] and the closure gap of the voiceless plosive, did not covary with the changes in VOT that accompanied perceptuo-motor adaptation. These results suggest that the perceptuo-motor effect observed for VOT does not merely reflect changes in stress and/or speaking rate, but rather fatique within a neural mechanism that controls the perception and production of either VOT or more specific variables associated with this coverall acoustic property. A model of the neural mechanism is proposed to account for the effects observed in both perceptual and perceptuo-motor adaptation experiments.

Subject Classification: 70.30, 70.20.
Response characteristics of polarized cathode solion linear acoustic transducers
Authors: English G. E. , Larkam C. W.
Published: October 2005

Solion is a generic term used to describe acoustic transducers which effect a charge transport by solution ions. Four general types of solion transducers may be distinguished on the basis of the mechanisms underlying the transducer action. One of these four, the polarized cathode type, is discussed in this paper. The polarized cathode solion is an infrasonic transducer for the pressure amplitude range of 10−3 μbar to 100 μbar. The frequency range is approximately 10−3 Hz to 0.5 Hz. A theoretical analysis of the polarized cathode acoustic linear transducer is summarized and compared with measured response characteristics. The conclusion is that measured data support the theory for good first-order approximations and thereby provide a rational basis, which has been lacking in the past, for the design of solions.

Subject Classification: 85.40, 85.54.
Deep-scattering-layer observations off New Zealand and comparison with other volume scattering measurements
Authors: Batzler W. E.
Published: October 2005

Acoustic volume scattering measurements using 5 and 12 kHz pulses and explosive signals were made during the 1971 winter season at 18 deep-water stations north and east of Auckland, New Zealand. Strong scattering layers (maximum volume scattering strengths −58 to −70 dB re 1 yd) were observed at depths of about 500 yd during daytime measurements at both 5 and 12 kHz. The number, location and depth of minor scattering layers are the principal station differences. Column strengths (column length about 1000 yd) obtained from pulse measurements do not vary greatly from station to station and show good agreement with column strengths from explosive measurements. Night values of column strength are higher, with one exception, than day values. The explosive results covering 1/3-octave bands from 1 to 20 kHz have overall column strengths ranging from −70 to −40 dB. A characteristic frequency pattern, in which a sharp rise in column strength from 1 to 5 kHz is followed by a fairly constant level thereafter, is exhibited on all stations. Comparison of the New Zealand data with that from other ocean areas (Indian Ocean, Coral Sea, Hawaii, Atlantic, Gulf of Mexico, Southern California) shows that New Zealand scattering strengths are relatively high and that the characteristic frequency pattern is of widespread occurrence. The prevalence of this pattern suggests a mechanism common to all these locations. Midwater fishes differing in species from area to area but having a common range of swimbladder sizes are believed the cause of this characteristic frequency pattern.

Subject Classification: 30.30,30.40.
Professor Walter G. Cady’s contributions to piezoelectricity and what followed from them
Authors: Mason Warren P.
Published: October 2005

In connection with a celebration of Professor Walter G. Cady’s approaching 100th birthday, a resume of some of his most important works on piezo and ferroelectric crystals were discussed. This celebration was held at Wesleyan University in Middletown, Connecticut where he was a professor for over 40 years. Briefly he was the inventor of the crystal-controlled oscillator, the very selective narrow-band crystal filter, one of the principal theorists of the ferroelectrical effect in crystals, and the historian par excellence of the science of piezoelectric crystals. These initial efforts have led to many applications, such as (1) crystal filters for separating out the many telephone channels that can be transmitted over radio systems, coaxial systems, and undersea cables; (2) crystal-controlled oscillators and time standards of use for radio broadcasting, navigation systems, and crystal-controlled watches; (3) ferroelectric crystals and ceramics which are widely used in such applications as ultrasonic cleaners, medical applications, devices for generating high voltages, and particularly in underwater sound transducers.

Subject Classification: 10.60; 85.52.
Diffraction of sonic boom past the nominal edge of the corridor
Authors: Onyeowu Ronald O.
Published: October 2005

According to ray acoustics sonic boom is limited to a ’’corridor’’ on the ground by atmospheric refraction. Beyond the edge of the corridor on either side lies a region void of incident or reflected rays—the ’’shadow zone’’—the treatment of which is beyond the scope of ray acoustics. In this paper, a technique is developed for extending the prediction of the sonic boom signature into the shadow zone using diffraction theory. The calculations indicate that the portion of this region lying along the horizontal plane boundary behaves like a low-pass acoustic filter. This has the effect of progressively rounding and attenuating the sonic boom signature as the shadow zone is penetrated—an observable characteristic of experimental records. In a separate calculation, an empirical variable reflection factor based on the angle of incidence of the shock wave in the sound field is obtained to correct the bell-shaped 3/4-power curve of amplitude variation across the corridor.

Subject Classification: 28.55 28.40; 20.30. 20.20.
Investigation of the amplitude fluctuations of high-frequency short-duration.sound pulses propagated under short-range shallow-water conditions
Authors: Andrews R. S. , Turner L. F.
Published: October 2005

This paper reports on part of a general investigation that has been carried out to determine the feasibility and limits of performance of high-data-rate underwater digital data communication. Specifically, the paper deals with the amplitude fluctuations that are encountered when high-frequency 0.8-msec duration pulses are transmitted under short-range shallow-water conditions. In the paper, the results of an analysis of experimentally measured amplitude fluctuations are presented. The results, which are presented in the form of amplitude-frequency spectra, autocorrelation functions, and probability density functions, are interpreted in terms of the prevailing climatic conditions, and the results are related to existing relevant theories of fluctuations.

Subject Classification: 30.20.
Viscoelastic model and acoustic wave propagation in anisotropic media
Authors: Vacher R. , Boyer L.
Published: October 2005

The model of the standard linear solid is extended to the viscoelastic anisotropic medium by defining a relaxation-time tensor. The velocity and attenuation of sound waves are calculated as a function of frequency from the components of this tensor and low- and high-frequency elastic constants. The anisotropic behavior of relaxation curves can be described in this formalism.

Subject Classification: 35.50.
Regulation of voice amplitude by the monkey
Authors: Sinnott Joan M. , Stebbins William C. , Moody David B.
Published: October 2005

Old World monkeys (Macaca) were trained to vocalize at a steady rate in the laboratory by the use of operant conditioning techniques with food as a reinforcer. While the animals were vocalizing, they were subjected to one of two noise bands (200–500 Hz or 8–16 kHz) at different sound pressure levels (70, 80, and 90 dB SPL). Vocal amplitude was measured as a function of the SPL of the noise bands. The monkeys increased voice amplitude to the band of low-frequency noise but not to the high-frequency band. These results suggest that in monkey, as in man, a relation exists between speaking and hearing: both man and monkey will increase voice amplitude in the presence of masking noise of the appropriate spectral composition.

Subject Classification: 65.22; 70.20.
Vowel duration in American English
Authors: Umeda Noriko
Published: October 2005

This is a summary report of the vowel duration data that have been accumulated over the past several years. The data corpus analyzed to derive temporal controls of vowels consists mainly of three different readings by three different speakers, each about 10 to 20 min in duration. The rules cover the temporal behavior of vowels under many phonological conditions. The conditions include stressed and unstressed positions, prepausal and nonprepausal positions, word-final and non-word-final conditions, and monosyllabic and polysyllabic words. The influence of following consonants is discussed as well. Included also are conditions other than phonological ones, such as the effect of the prominence of words on their vowels, and the speed of reading. The duration rules derived from the data are intended for use in our speech synthesis-by-rule system from printed text.

Subject Classification: 70.20, 70.70.
Effect of the number of frames on the sound radiated by fluid loaded, frame-stiffened plates
Authors: Garrelick Joel M. , Lin Gau-Feng
Published: October 2005

The on-axis pressure radiated by a point-excited, fluid loaded, frame stiffened plate is considered. In particular the practical ramifications of employing the simplifying assumption of an infinitely periodic array of frames are explored. Numerical results for framing arrays consisting of two, four, and an infinite number of frames are compared.

Subject Classification: 20.60; 25.55.
Northeastern Pacific sound attenuation using low-frequency CW sources
Authors: Lovett J. R.
Published: October 2005

CW acoustic transmissions received by ship-suspended hydrophones from seamount emplanted sources off San Diego of 750, 1500, and 3000 Hz; and submarine sonars of 1500 and 2500 Hz in the Gulf of Alaska result in attenuation coefficients significantly below values given by Thorp’s equation. The present data, and the Sheehy–Halley very-low-frequency Pacific data, suggest a modified equation for CW transmissions.

Subject Classification: 30.20.
Measurement of frequency responses and the multiple coherence function of the noise-generation system of a diesel engine
Authors: Chung J. Y. , Crocker Malcolm J. , Hamilton James F.
Published: October 2005

A structural–acoustical system has been established to model theoretically the noise generation of a six-cylinder diesel engine. In this system, six-cylinder pressures have been treated as six mutually correlated inputs. The noise measured 3 ft away from the engine has been treated as the single output of the system. Six structural–acoustical frequency responses with respect to the six inputs were evaluated experimentally. The multiple coherence function between all the inputs and the single output has also been evaluated experimentally. Using the multiple coherence function, the engine noise which is coherent to the cylinder pressures was separated from the total engine noise. It has been found that, for the V-6 diesel engine studied, the coherent noise is almost equal to the total noise. From the structural–acoustical frequency responses, the contributions of the individual cylinder pressures to the coherent engine noise were assessed.

Subject Classification: 50.50; 60.20.
Changing role of the ’’expert’’
Authors: Beranek Leo L.
Published: October 2005

The evolution of acoustical consulting over the past 40 years is traced from the early days of simple measurement and little technical information through to the emergence of the consultant as a central participant in the quieting of large machines and airfleets that affect the lives at work and at home of large segments of the population. The part the acoustical consultant plays in national noise regulation and control is discussed. Acoustical consultants are urged to take a broader view of their intraprofessional relationships and raise their level of professionalism, not only to their clients but also to each other.

Subject Classification: 10.60, 50.10, 55.10.
On digital spectrum analysis of periodic signals
Authors: Burgess John C.
Published: October 2005

Digital spectrum analysis of harmonic signals can result in amplitude estimates in error as much as 3.92 dB. The corresponding frequency estimates are not exact. The paper presents a general method for obtaining significantly improved estimates of amplitude and frequency. Criteria are given which allow specification of an error limit. Specific equations are given for sample signals that are unmodified (open window) and for signals modified by a Hanning data window. The phenomenon called ’’leakage’’ is shown to result from discontinuities imposed by the computation process at the periodically extended ’’ends’’ of a sample signal and not, as is often supposed, by discontinuities presumed to (but do not) exist at the ’’ends’’ of the open window. Criteria for window selection to reduce leakage are discussed. Calibration is specifically treated. When any data window other than the open window is used, a different calibration must be applied to periodic and random components in a signal. Although discussion is limited to a single harmonic signal, the method can be applied in a straightforward way to signals with multiple harmonics.

Subject Classification: 10.60; 60.10; 30.80; 40.60; 50.85, 60.50; 85.32, 85.84.
Short-wavelength acoustic diffraction by prolate spheroids
Authors: Lauchle Gerald C.
Published: October 2005

The scattering of a plane acoustic wave by a rigid prolate spheroid of large fineness ratio is investigated analytically. The solution for the diffracted field is presented in terms of the classic modal series of spheroidal harmonics. The series are numerically evaluated for wavelengths much smaller than the length of the spheroid, but comparable to the minor radius. For this range of wavenumbers, use was made of available asymptotic formulas of the spheroidal wave functions, where the convergence of the double infinite series is discussed in terms of the value of the product of wavenumber and various characteristic lengths of the spheroid. The directivity functions are presented for several values of plane-wave incidence, reduced frequency, and fineness ratio. The total scattering cross section is evaluated and compared to the scattering cross section of rigid spheres. An estimate is given to the size sphere required to scatter approximately the same power as the spheroid of given size and orientation with respect to the incoming plane wave.

Subject Classification: 20.15, 20.30.
Fluctuations of narrow-band sound amplitudes from long-range transmissions in the deep Atlantic Ocean
Authors: Baxter Lincoln , Yang C. Y.
Published: October 2005

For transmission paths between a fixed acoustic source at 527-m depth near Eleuthera and a fixed receiver at 1723 m near Bermuda, G. E. Stanford [J. Acoust. Soc. Am. 55, 968–977 (1974)] has shown that the spectrum of fluctuations in acoustic intensity is nearly flat up to 3 cycles/h and drops off as 1/f3 above this frequency. For comparison with internal gravity wave disturbances of the sound velocity profile, we have analyzed amplitude fluctuations of transmissions from floats deployed as part of the 1973 series of Mid-Ocean Dynamics Experiments (MODE). These floats carrying 30-W input, 270-Hz sound sources pulsed for 1.67 sec at 3-min intervals were released to drift near 28°N,70°W at a depth of approximately 1500 m. The transmissions were received by fixed hydrophones (MILS system), located on the sound channel axis on the slopes of Eleuthera and Grand Turk. We find a spectrum similar to that of Stanford except that the 1/f3 characteristic begins at 1 cycle/h. For each experiment this rolloff frequency coincides approximately with the Brunt–Väisälä frequency at the turning points of those SOFAR paths with minimum excursion from the axis.

Subject Classification: 30.20.
Bayes optimum array detection of targets of known location
Authors: Adams S. L. , Nolte L. W.
Published: October 2005

This paper presents a Bayes optimum approach to detecting a target of known location by processing the outputs of an array of sensors. Beamforming is not postulated a priori. The complex exponential Fourier series is used to represent the deterministic signals and random processes. Using Bayes decision theory, important existing results and new results are unified and presented in a single mathematical framework. Optimum receiver structures and performance are derived for detecting a known signal source in a Gaussian noise field. They are also derived for detecting a signal source which generates an uncertain waveform in either a spatially uncorrelated noise field or a noise field with spatial correlation due to a farfield noise source. Important new results concerning factorization of optimum array receivers are presented for detecting signal sources of known location which generate either known or uncertain waveforms. A technique for applying existing scalar results to array problems is presented for several cases. Detection performance results, in terms of the receiver operating characteristics (ROC), which are characterized in some cases by the detectability index, are presented for a number of situations.

Subject Classifications: 60.20; 25.35.
Correlation function of the field between arbitrarily oriented points for a plane wave in a random medium
Authors: Fitelson M. M.
Published: October 2005

This paper is concerned with the correlation between arbitrarily oriented points for a plane wave propagating in a statistically homogeneous and isotropic medium. The bearing response pattern of a line array in such a medium is obtained and numerical results are presented.

Subject Classification: 60.20; 30.20; 60.30.