bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensitivity loss over task-time during hour-long auditory sessions
Authors: Kaplan R. A. , Hafter E. R.
Published: October 2005

Use of YES-NO procedures may yield biased estimates of sensitivity because of failure to meet certain assumptions of the detection model. Estimation problems are increased in long-time tasks because of interactions between increasingly strict criteria and the asymmetry of the ROC. A two-alternative forced-choice paradigm was employed to establish, as nearly as possible, the time course of sensitivity. Signals were 100-msec bursts of 500-Hz tones embedded in 1-sec bursts of wide-band noise. Trials were presented 15/min over one-hour sessions. Performance dropped within sessions by about 2 dB. A long-standing theory which would account for such a decrement postulates an attentional filter which may vary over task time [Broadbent, Perception and Communication (1958)]. This suggests a modification of the effective masker due either to a widening of the bandwidth or to a variation of its center frequency. Observers were tested in a counterbalanced procedure utilizing two new conditions in addition to our standard task. Using narrow-band (475–525 Hz) noise, we found a significant reduction in the decrement in detection over time. When a wide-band noise was used, the presentation of frequency cues on each trial reduced the decrement. The results support the notion of an internal auditory filter which varies over time.
Reflection and diffraction from prolate spheroids
Authors: Lang Mark
Published: October 2005

Much theoretical material has been published on acoustic scattering by simple geometries, but in most cases numerical results are limited to asymptotic cases. This paper describes an experimental set-up at Penn State designed to make diffraction measurements in air at frequencies up to 40 kHz, providing for convenient use of models 1–100 wavelengths in dimension. It also presents the results of a study done on the prolate spheroid to determine the sources of reflection and diffraction at various angles of incidence. These results show that a body having two radii of curvature and no surface discontinuities scatters very little energy, and that what is scattered can be attributed soley to “specular” reflection. Examples are shown which demonstrate that, for the range of frequencies used, the results can be accurately predicted by simple geometric calculations.
Remarks on the theory of aerodynamic noise
Authors: Pan Y. S.
Published: October 2005

Lighthill's theory of aerodynamic noise has been the foundation of the current noise research. The theory is exact and based on an acoustic analogy. The source strength, however, can be found only when the problem is solved. To make a quantitative calculation, one has to make various approximations to the theory. The present study provides a critical evaluation of these approximations, Based on a matched asymptotic method, Navier-Stokes equations are expanded in Mach number. To the first order, the flow field (M2) is generally nonisentropic. The pressure is generated by the incompressible Reynolds stresses in the flow and the normal stress and velocity fluctuation on the surface. The acoustic field (M5) is obtained by matching with the flow field. Acoustic pressures in both stationary and moving media are obtained. Surprisingly, the first-order noise generation does not depend upon the thermal and entropy effects in the flow and the shear stress on the surface. Comparisons with previous works and discussions of possible new approaches on aerodynamic noise are made.
Acoustic eigenmodes of corrugated ducts
Authors: Succi George P.
Published: October 2005

Acoustic propagation in two-dimensional corrugated ducts is analyzed. A transform is made to a coordinate system that matches the duct walls. The resulting wave equation separates in space and time. The spatial differential equation is then solved by expanding in the eigenfunctions of a flat-walled duct. The prescription for this expansion is given by the appropriate application of time-independent perturbation theory. Calculations of first-order corrections for sinusoidal ducts of finite and infinite length are presented. A general conformal transform for symmetric ducts of arbitrary cross section is also included. [This work was supported by NASA Lewis Research Center under Research Grant NGR 22-009-805.]
Procedure to predict the propagation of sound in absorbent ducts with nonuniform areas of cross section
Authors: Vaidya P. G.
Published: October 2005

A finite-length Green's function has been developed for propagation of higher-order modes of sound in ducts. This function is used to obtain a linear integral equation. A procedure for the solution of this equation is described. This method is extended to include flows.
Computational model of the tongue
Authors: Kiritani S. , Miyawaki K. , Fujimura O. , Miller J. E.
Published: October 2005

A computer program for simulation of the tongue as a three-dimensional static elastic system has been written for studying the physiological functions of certain extrinsic and intrinsic muscles in speech production. Forty-four tetrahedra are employed to represent one-half of the tongue, assuming symmetry in respect to the midsagittal plane. Uniform stress and strain distribution is assumed in each tetrahedron, with elastic constants representing an approximate volume incompressibility, and displacements of the nodal points (vertices) are calculated by the finite-element method. The entire set of tetrahedra are grouped into 14 functional units, each of which can be given independently specified uniform stress in any direction representing an independent muscle contraction. In addition, specific node points can be pulled by an external force. Computation is made iteratively a few times for a given set of muscle contractions deriving a deformation consistent with palatal and other boundary constraints. The resultant shape is displayed in stereopsis with a knob-controlled viewing angle.
Propagation of high-intensity higher-order mode sounds in absorbent ducts
Authors: Vaidya P. G. , Wang K. S. , Shashaani G. R.
Published: October 2005

Propagation of higher-order modes of sound in absorbent ducts is described by using a modified weighted residue method. A modified perturbation technique is employed. The higher-order modes, even in presence of rigid walls, generate other modes. Some of the results from the theory are compared with experimental results.
Measurement of sound transmission loss as a function of incidence angle
Authors: Walker Bruce
Published: October 2005

The formulation for sound transmission through a panel generally credited to Cremer gives poor agreement with experimental results when calculated random incidence transmission is compared to reverberant field measured transmission, The usual solution to this problem is a truncation of the calculation somewhere short of grazing incidence, and definition of the result so calculated as the “field incidence” transmission. In the present study, sound transmission through a presumably predictable material (0.5 psf leaded vinyl sheet) has been measured using free-field excitation at several discrete incidence angles and a small reverberation room as a receiving room. Initial results indicate that behavior between 70° and grazing incidence is smooth, but in poor agreement with Cremer's formulation, with transmitted sound power nearly independent of incidence angle in this range. A proposed practical redefinition of sound transmission loss and finite panel corrections to the Cremer formulation is discussed.
Psychophysical tuning curves of chinchillas
Authors: McGee Therese , Ryan Allen , Dallos Peter
Published: October 2005

When in a tone-on-tone masking experiment the threshold of a low-level, constant-frequency maskee is obtained as a function of the level and frequency of the masker, an approximate equivalent of a single-unit neural tuning curve is generated [A. Small Jr., J. Acoust. Soc. Am. 31, 1619–1625 (1959); E. Zwicker, in Facts and Models in Hearing (Springer-Verlag, New York, 1974), pp. 132–139]. Since these curves have proven to be of value in assessing various auditory phenomena in human listeners, it was deemed appropriate to adapt them for use in an animal model. To this end, chinchillas were trained in a shock-avoidance task and their psychophysical tuning curves were obtained. Two procedures were employed for comparison; simultaneous and forward masking. Curves were obtained at several maskee frequencies in order to compare their shapes and the sharpness of tuning. [Working supported by grants from the NINDS.]
Mechanisms of auditory masking
Authors: Ryan Allen , Dallos Peter
Published: October 2005

Psychephysical “tuning curves” [e.g., A.M. Small Jr., J. Acoust. Soc. Am. 31, 1619–1625 (1959)] were collected from chinchillas trained with the shock-avoidance method. Tonal maskers were used in both a simultaneous and forward-masking paradigm. The experiments were performed before and after administration of kanamycin. The drug dosage was controlled so that relatively pure outer hair cell lesions were obtained in the basal region of the cochlea, resulting in a high-frequency threshold shift of about 40 dB while low-frequency hearing remained normal. That portion of a two-tone masking curve which was located within the area of threshold shift was shifted proportionally. That portion outside of the lesion had a configuration which indicated that the amount of masking was dependent on the threshold shift of the masker, rather than the maskee. This finding implies that masking is not mediated by that segment of the cochlea alone that responds to the maskee, but that either longitudinal cochlear interactions occur or some central influence on simple masking needs to be considered. To further examine this problem, pure-tone masking “tuning curves”of the whole-nerve action potential were also measured in normal and kanamycin-treated animals. These curves largely paralleled the behavioral results, suggesting that the observed phenomena are mediated in the cochlea, rather than the central nervous system.
Comparison of susceptibility to impulse-noise-induced threshold shift: chinchilla and man
Authors: Woodford C. M. , Sitler R. S. , Kozelsky J.
Published: October 2005

Species-specific differences in susceptibility to threshold shift induced by impulse noise are often important considerations in noise research. Luz and Hedge (1971) and Luz and Lipscomb (1973) have suggested that the chinchilla is more susceptible to very brief (A) duration (50 μsec) impulse-noise-induced threshold shift than is man. The present study was undertaken to make a direct comparison between chinchilla and man as to threshold shift produced by impulse noise. Two chinchilla and two humans determined to have hearing and middle-ear function within normal limits were exposed to five impulses of 154-dB intensity, 15 msec (A) duration, at a rate of 1/30 sec. Auditory threshold was estimated via the auditory evoked response method with the chinchilla while human subjects tracked threshold. Each subject was tested on a fixed schedule following exposure. Threshold shift in the chinchilla at 2-h postexposure was found to be up to 40 dB more severe than for the human subjects. Recovery to pre-exposure levels required up to seven days for the chinchilla, while the human subjects recovered within 48 h.
Binaural interaction in cat and man. IV. Critical bands
Authors: Langford Ted L. , Hoppe Susan A.
Published: October 2005

Data from the first and third papers in this series [S. A. Hoppe and T. L. Langford, J. Acoust. Soc. Am. 55, 1263–1265 (1974); T. L. Langford and B. H. Geesa, J. Acoust. Soc. Am. 55, S51(A) (1974)] suggest, as do comparisons of cat and human anatomical data, that the cat should exhibit a wider critical band than the human. Using the same experimental methods as those in the previous papers, the critical band at 500 Hz was measured for the cat for the stimulus conditions N0S0 and NπS0 and compared with similar human data. The lower side of the critical band was measured by raising the lower cutoff frequency of a high-pass-filtered masker while adjusting the signal level to maintain a constant level of performance. Similarly, the upper side of the critical band was measured by lowering the cutoff of a low-pass noise filter. The results show a wider critical band for the cat than for man for both diotic and dichotic conditions, while both species have narrower diotic than dichotic bandwidths. [Supported by a grant from NSF.]
Study of the liquid-state electromagnetic transducer
Authors: Ajisaka Hidemi , Hixson E. L.
Published: October 2005

The electromagnetic effect, F⃗ = (I⃗ × B⃗)l, E⃗ = (V⃗ × B⃗)l, for a conducting fluid in a duct is studied as an acoustic transducer. For the two acoustic ports and the electrical port, three-port parameters result that are functions of such physical parameters as the duct size, fluid conductance, wave speed in the duct, and magnetic flux density. To check the analytical model, salt water was used in a square duct of anodized aluminum. The 1.5 in. × 1.5 in. × 6 in. duct was placed in magnetic field that could be increased up to 0.8 webers/m2. Good agreement for the model was obtained over the range of 200–4000 Hz. Finally, source and receiving sensitivities and efficiencies are calculated.
Electret coaxial cable hydrophone performance
Authors: Miller G. K.
Published: October 2005

A machine-fabricated coaxial cable with FEP—teflon for dielectric and jacket was thermoelectrically treated to pole the dielectric layer. Segments of the resulting electret cable were sealed and tested for sensitivity to underwater acoustic signals over the frequency range 10–1000 Hz, the ambient pressure range 0–17 MPa, and at a few temperatures down to 5 °C. The initial sensitivity of a 0.5-m-long sample is about −169 dB re 1 pC/μPa. Although the sensitivities of most samples were found to be nearly independent of temperature and frequency, they were significantly affected by ambient pressure. The complicated dependence of sensitivity on ambient pressure is explained and verified on the basis of additional experiments and on the basis of a mathematical model derived for this transducer.
Effects of control valve nonlinearity on the output of hydro-acoustic transducers
Authors: Woollett Ralph S.
Published: October 2005

An underwater sound source using a hydraulic-drive mechanism is subject to signal distortion produced by the electrohydraulic control valve. The nonlinear characteristics of the commonly used valves are described reasonably accurately by a well-known equation derived from Bernoulli's law. A numerical study was made of the effects of the valve nonlinearity on transducer performance, using the Runge-Kutta-Gill algorithm to solve the nonlinear differential equations. Load lines and waveforms were plotted and Fourier distortion components computed for typical operating conditions. The results show that the limitations necessary on the pressure modulation coefficient for low output distortion and show the benefits of resonance in providing a favorable load line, thus confirming and quantifying the design principles used by those who developed the hydroacoustic transducer art.
Conditions for the inference of upper-bound estimates of sound power from close-in measurements of sound pressure
Authors: Holmer C. I. , Flynn D. R.
Published: October 2005

Current measurement standards do not provide adequate guidance for the evaluation of the uncertainty involved in using measured sound pressures, rather than sound intensities, to estimate the sound power radiated by a source. In this presentation, conditions are derived which are sufficient to ensure that an estimate of sound power based on close-in sound-pressure measurements over a surface enveloping the source (in a free field or free field over a reflecting plane) is, in fact, for perfect sampling, an upper bound to the true sound power. Conditions for this upper bound to be the least upper bound are also derived for the case of the absence of a priori information regarding the directivity of the source. Experimental data are presented which support the analytical findings. Some implications of sampling error in the measurement process are also discussed.
Acoustical design of Cincinnati Music Hall organ installation
Authors: Martin Daniel W. , Stein John L.
Published: October 2005

A Baldwin custom Multi-Waveform organ was recently donated by the Corbett Foundation for a permanent installation in Cincinnati Music Hall's 3700-seat auditorium, for use by the Cincinnati Symphony, the May Festival Chorus, the Summer Opera, and the Ballet. Because this old auditorium has an outstanding reputation, no changes permanently affecting either its acoustics or its appearance were permitted. Two high arrays of electroacoustic pipes, radiating tones upward on each side of the proscenium, are supported on movable platforms at stage level. They are supplemented by additional invisible tone sources high above the stage, which are mounted in the existing proscenium arch wall, and by two large pedal tone cabinets for the infrasonic frequency range which radiate through tuned ducted ports into the auditorium. Thus, the tone is produced within the auditorium, rather than the orchestra shell or the stagehouse, and surrounds the large stage opening, distributing and blending the tones for both performers and the listeners.
Reverberation test suite design in high noise area
Authors: Mason John M.
Published: October 2005

The procedures adopted in the design of a reverberation test suite to be located in a noisy industrial area are presented. The acoustical specifications of the facility necessary to enable sound-power measurement evaluations of fluorescent-tube lighting ballast units are briefly reviewed. Objective noise data obtained on site prior to construction are given, and this information, in conjunction with desirable internal acoustical criteria, is employed to derive acoustical insulation specifications. The procedures adopted in the determination of these specifications are presented. The architectural and economic implications of the insulation requirements are examined and preliminary architectural schematics of the construction are described. An outline is given of the methodology used for site supervision during the construction process and of the planned testing for contractor compliance on the completed facility.
Noise control for air-conditioning systems installed in the Philadelphia Academy of Music and Boston Symphony Hall
Authors: Hoover R. M. , Curtis J. A. , Jones R. S.
Published: October 2005

In recent years full air-conditioning systems have been installed in the Philadephia Academy of Music and in the Boston Symphony Hall, replacing the original heating and ventilating systems. In this paper the new air-conditioning systems are briefly described, and the steps that were taken at each hall to control the system noise levels are reviewed. Noise levels measured in various seating sections of each hall with the air-conditioning system operating are reported and compared with previous conditions.
Effect of a time-varying boundary on the sound field in an enclosure. I
Authors: Hwang Y-F. , Tichy J.
Published: October 2005

This paper presents a theoretical study of the sound field in a rectangular enclosure with one wall moving as a piston. In order to express the time-varying boundary condition, a coordinate transformation was used, which transforms the incident wave coordinate system into another system moving with the wall. The sound field in the enclosure was derived for a point source, considering the enclosure as a rectangular duct with one termination fixed and one oscillating. As a result, the velocity potential can be calculated in any point of the enclosure for an arbitrary source location with given parameters of the wall oscillations.
Projection of diesel engine noise in mines from above-ground measurements
Authors: Galaitsis A. G. , Patterson W. N.
Published: October 2005

Underground noise levels of diesel engines were projected from above-ground measurements to set noise reduction goals meeting mine safety standards. Projection schemes applying to large spaces do not apply to most underground spaces which are tunnels (length ≫ width, height) or flat rooms (spread ≫ height). The sound-pressure level in the reverberant region of a large space is fairly constant but decreases monotonically with distance from the source along the length of a tunnel or the spread of a flat room. A method resembling that of Yamamoto [J. Acoust. Sec. Jap. 17, 26 (1961)] was used to project underground SPL for different values and combinations of the wall absorption coefficients and for various distances of the source and observer from the walls. All engines were approximated by point sources, the boundaries were replaced by an equivalent set of images, and the contributions from all sources were added in an uncorrelated fashion. Direct measurements performed at several mines support this projection method. [This work was sponsored by the United States Bureau of Mines. ]
Perception of vowel duration in sentence contexts
Authors: Klatt D. H. , Cooper W. E.
Published: October 2005

The duration of a word such as “deal” ranges from about 310 msec in phrase-final positions in a sentence to as little as 160 msec when used in the phrase “dealer's choice.” A magnitude estimation technique has been used to quantify the expected duration and perceptual tolerance limits for the syllable “deal” in different spoken sentences, where one or more pitch periods of the vowel have been removed or duplicated. Results indicate that listeners adjust their expectations of vowel duration depending on the syntactic position of the vowel in the sentence and the syllable position of the vowel in a word. Thus, the longer durations for phrase-final syllables that were observed previously by one of the authors are part of an English listener's perceptual scheme.
Discrimination of formant-like transitions without phonetic context
Authors: Pastore R. E. , Ahroon W. A.
Published: October 2005

A recent study by Dorman [Percept. Psychophys. 16, 84 (1974)] claimed to demonstrate that the ability of human observers to discriminate intensity differences in the initial portion of a stimulus is dependent upon the presence or absence of a phonetic context to the stimulus. This study rejected backward masking as a factor and conjectured that the phonetic stimulus might have activated a special phonetic process which differed from the normal processing of the acoustic properties of the stimulus, and which resulted in the phonetic information being stored in a relatively inaccessible portion of short-term memory. The Dorman study was replicated using various simple stimuli generated from pure tones and an FM-glide. The results of both studies are discussed in terms of the relevant acoustic properties of the stimuli.
Masking-like phenomena in speech perception
Authors: Dorman M. F. , Raphael Lawrence J. , Liberman A. M. , Repp Bruno
Published: October 2005

To study masking-like effects in the perception of continuous speech, we presented two-formant syllables /b ε b/ or /b ε g/ followed, at intervals from 0 to 150 msec, by /d ε/; listeners were instructed to identify the syllable-final consonant. An 80-msec intersyllable interval was required for recognition of syllable-final consonant to reach asymptote. To determine the level at which this “masking” occurred, we repeated the experiment, but with the second-formant transitions of the first syllable presented alone for judgment as rising or falling chirps. Recognition of the isolated transitions (chirps) was essentially unaffected, no matter what the interval between them and the second syllable. These data suggest that the “masking” in the initial study was due to the elimination of a necessary cue—in this case, a silent interval, corresponding to the stop closure, between the syllables—and not to backward masking of the auditory information. In a third study, we found that changing voice between the syllables from male to female also eliminated almost all the “masking.” This reinforces the conclusion of the first two studies, indicating in this case that the effect is not to be attributed to interruption of processing, but raises other questions that we have only begun to investigate.
Effect of consonantal environment on the identification of speakers' own vowels
Authors: Carney A. E. , Edman T. , Strange W. , Jenkins J. J.
Published: October 2005

A “normalization” hypothesis of vowel perception assumes that a listener identifies the vowels of an unfamiliar speaker, at least in part, by reference to vocal-tract information supplied by a prior sample of the speaker's vowel production. This assumption has been questioned by previous research [W. Strange, R. Verbrugge, and D. Shankweiler, “Consonant environment specifies vowel identity,” Status Report on Speech Research, SR-37/38, 209–216 (1974)] in which the presence of consonantal environment was shown to be more important for accurate vowel identification than previous experience with the speaker's vocal tracts. In this research, familiarization was restricted to a small number of test utterances. A more stringent test can be designed by asking a subject to identify his own vowel productions. Three representative talkers (man, woman, and child) recorded tokens of nine American English vowels in two contexts—in isolation and in a fixed consonantal environment (/p-vowel-p/). These speakers then acted as listeners for their own and the two other speakers' vowels. Results indicated a small advantage in listening to one's own isolated vowels; this advantage disappeared for vowels in consonantal context. More importantly, vowels in consonantal context yielded significantly fewer errors than did isolated vowels for all subjects, both on their own vowel productions and those of other subjects.
Noise control and its economic implications
Authors: Warnaka Glenn E. , Johnson Jerry G. , Sass Hans J.
Published: October 2005

In determining the cost of noise control many things must be considered. Direct costs which include original cost of equipment, installation costs, maintenance costs, operating costs, etc., are relatively easy to evaluate. However, noise control also provides a series of benefits that are, unfortunately, more difficult to assess These include lowered insurance premiums, fewer compensation claims, reduced fines, better communication between management and labor, possibly better morale, and increased efficiency. The actual cost of noise control can only be determined by considering factors that reduce costs as well as those that add costs. It is also important to recognize that noise control has not previously been practiced on a large scale. Thus, past and current costs cannot be linearly extrapolated to future conditions. The effects of large-scale production and technological advances should substantially reduce costs. This paper presents an overall view of the parameters that will ultimately determine cost of noise control.
Costs and benefits of noise control in the petroleum industry
Authors: Bruce Robert D.
Published: October 2005

Noise from industrial operations has become widely recognized as a potential hazard to health. industry, labor, and government share a common interest in assessing the hazard and reducing it to a socially acceptable risk. Achieving these ends requires the use of information about the amounts of noise exposure encountered, the relation of exposure to risk, and the costs of noise control required to achieve specified benefits. Such information pertaining specifically to the petroleum industry is the subject of this paper. We report here some estimates of benefits and costs aggregated for the petroleum industry. We define the benefits as reduced incidence of hearing damage in refinery workers in relation to certain existing and proposed Federal regulations. For such category of regulation we estimate the number of refinery workers now exposed to noise that exceeds the regulated amount, and we estimate the national cost of reducing the noise to the regulated amount.
Dichotic and monotic interactions between speech and nonspeech sounds at different stimulus-onset-asynchronies
Authors: Mirabile Paul , Porter Robert J.
Published: October 2005

Target CVs were presented in monotic and dichotic competition with four “challenges” (1) nonspeech parts of CVs, (2) nonspeech “sweeps” of formants, (3) “CV-noise,” made by averaging the waveforms of the targets, and (4) another CV. Subjects were asked to identify targets whose onset led or lagged challenge onset by 0, 20, 40, and 60 msec. A dichotic “lag effect” (better performance on lagging than on leading targets) and a monotic “lead effect” (better performance on leading than on lagging targets) were observed for all challenges. The lead and lag effects appeared to depend on different aspects of the acoustic structure of the challenges, however. The results are interpreted in the context of a model which distinguishes between “peripheral” auditory, “central” auditory, and phonetic processing. [Supported by NIH USPHS Grant NH 11647-01.]
Dichotic right-ear advantages with “bleats”
Authors: Berlin Charles I. , Hughes Larry F. , Berlin Harriet , Cullen John K.
Published: October 2005

Synthetic CVs competed against “bleats” (second and third formant transitions, both kindly supplied to us by D. Pisoni and colleagues) alternately in the right and left ears of 10 subjects. Both right and left ears were suppressed by the presence of the bleat in the other ear, but the left ear suffered more interference than the right ear. The nonsemantic and unintelligible nature of the bleats, coupled with their ability to generate an REA when competing against CVs, heightens the importance of acoustic factors in the dichotic right-ear advantage for CVs. However, the results do not suggest that there are no other contributing factors to the REA, and should not be so construed. [Supported by National Institutes of Health, USPHS Grant No. NH 11647-01.]
Cue-specific adaptation to speech sounds
Authors: Bailey P. J. , Haggard M. P.
Published: October 2005

The position of the phoneme boundary on an acoustical continuum between two CV test syllables can be shifted by prior repetition of an adapting CV syllable. Our experiments show that repeated exposure to a distinct /ba/ or /da/ adapter whose place of articulation is cued only by transitions of the third formant, with a fixed, ambiguous value of the second formant, does not shift the phonome boundary on a /ba/-/da/ test series if the test stimuli have no third formant and are cued by transitions of the second formant. However, the same adapters will shift the phoneme boundary of an otherwise similar test series which has a neutral transitionless fixed third formant. We interpret this result as indicating that (i) transitions of the second and third formants are processed independently at peripheral levels, and (ii) a substantial proportion of the place adaptation effect in CV syllables distinguished by characteristics of the formant transitions is at the level of detectors for acoustical cues, not at the level of categorical perceptual decisions or response organization. This does not deny the existence of other types and dimensions of adaptation effect.
Method for computing sonar response to aft bearing noise sources
Authors: DeWoody R. T. , Testen J. C.
Published: October 2005

The search sonar on some ships has a cylindrical array shielded from its own ship's noise by a baffle. The sound-pressure levels on the cylindrical surface due to machinery and propeller noise cannot be computed by methods presented in the literature. An airborne scale model was constructured and the measured sound-pressure levels used to evaluate baffle effectiveness. The same method was applied to a ficticious sonar array and the measured levels were used to compute the sonar response as the beam was steered from 0° to 360°. The pure-tone source frequency and baffle length were varied to examine their contribution on baffle effectiveness. The average reduction in sonar response, over the front 180°, was used to evaluate baffle effectiveness.
Perceptual processing time in audition
Authors: Massaro Dominic W.
Published: October 2005

Previous studies have shown that time is required to resolve the pitch or loudness of pure tones and the sound of vowels, consonant-vowel, and vowel-consonant syllables. The task involves a backward recognition masking paradigm in which a short test sound is followed by an equally loud masking sound after a variable silent intersound interval. The identification of the test sound as one of a fixed number of alternatives improves with increases in the duration of the silent interval out to roughly 1/4 sec. Similar results are found in a successive same-different comparison task when the masking sound is presented after the second sound. The time to resolve the spatial location of a sound was also measured in these tasks. Subjects localized a short test sound followed by a masking sound, after a variable silent interval. The results are discussed in terms of current theories of auditory information processing.
Ototoxic potentiation between ethacrynic acid and amino-glycoside antibiotics in guinea pigs
Authors: Hawkins J. E. , Marques D. M. , Clark C. S. , Preston R. E.
Published: October 2005

In laboratory animals the diuretic ethacrynic acid exerts an ototoxic action that is usually transitory, but when given in conjunction with a single large dose of kanamycin it can cause permanent loss of cochlear function and of hair cells [B.A. West et al., Arch. Otolaryngol. 98, 32–37 (1973)]. Following such combined treatment we have found two distinct phases of pathological change in the cochlea, viz., an apparently reversible vesiculation of stria vascularis, followed two days later by injury to the suprastrial spiral ligament and destruction of the hair cells. Timing of the injections appears to be critical. Kanamycin or neomycin 50 mg/kg is effective if it precedes ethacrynic acid by one hour, but not if the order is reversed. The ototoxic potentiation presumably depends upon a breakdown of the hemato-labyrinthine barrier for the antibiotic by the diuretic, or vice versa. It offers the possibility of a quick screening test for ototoxicity of new drugs of either class. [Supported by USPHS Research Grant NS 05065 and Program Project Grant NS 05785.]
Hyaluronic acid salt—a mechanoelectrical transducer
Authors: Barrett T. W.
Published: October 2005

If hyaluronic acid salt is placed in a U-tube and gentle pressure is applied to one arm of the tube, a potential develops across the arms of the tube [Jensen et al. Nature 174, 1101 (1954)]. The effect appears dependent upon the existence of a layer remaining on the sides of the container. Recording with Ag-AgCl electrodes, potentials of up to 120 mV-the leading arm always of positive polarity—were obtained between the arms of a U-tube filled with 0.5-cc hyaluronic acid in 0.25-cc salt solution. The salt was: 107.1 mEq/ml Cl; 15.8 Na; 137.7 K, in analogy to the cochlear endolymph [Smith et al., The Laryngoscope 64, 141 (1954)]. Grounding one arm of the U-tube nullifies the effect. The experiment was repeated using a quartz photocell and optical rotary dispersion (ORD) meter. The ORD obtained is different according to the pressure and will change from a right to a left rotation. The extent of the rotation greatly exceeded the maximum range (±2°) of the instrument used (JASCO ORD/UV5). Hyaluronic acid is present at many body locations, e.g., Spoendlin [Hearing Mechanisms in Vertebrates (1968)] has demonstrated that the space between the hair cells is filled with acid mucopolysaccharides. As different molecular conformations indicate different amounts of free energy, the mechanoelectrical transducing properties of both hyaluronic acid salt and the correct conditions might be of importance in understanding the cochlear generator potential.
Effect of inter-stimulus interval on the production of hearing loss from impulse noise
Authors: Perkins Carol , Hamernik R. P. , Henderson D.
Published: October 2005

Two groups of monaural chinchilla were exposed to 50 155-dB p.e. SPL, 1-msec “A” duration impulses in an anechoic environment. Two interstimulus intervals (ISI) were used: 10 sec and 1 min. Pre- and postexposure measured of hearing were obtained by the auditory evoked response, and the status of all cochleas was determined by the surface preparation technique. The 10-sec ISI exposure produced nearly total losses of outer hair cells throughout the entire cochlea and from 25% to 50% losses of inner hair cells. All animals in this group had excessive TTS (50–90 dB) and median PTS values of 25–30 dB across the 0.25–8-kHz range. The 1-min ISI group, on the average, had significantly smaller hair cell losses, especially inner hair cells. Audiometrically, there was less TTS, and either no PTS or significantly smaller values of PTS, i.e., 0–15 dB across the 0.25–8-kHz range.
Effect of impulse level on the interaction between impulse and continuous noise
Authors: Hunt W. , Hamernik R. P. , Henderson D.
Published: October 2005

An unexpected and traumatic interaction between individually safe levels of impulse and continuous noise has been demonstrated [R. P. Hamernik et al., J. Acoust. Soc. Am. 55, 117 (1974)]. The purpose of this study was to determine the level of the impulse that is necessary for the interaction effect. Three groups of five monaural chinchilla were exposed, in anechoic surroundings. Each exposure lasted one hour and consisted of a combination of 95 dB, 2–4 kHz noise and 50 40-μsec “A” duration impulses presented 1/min, having either 147, 142, or 137 dB p.e. SPL. Hearing was evaluated using the auditory evoked response, and the status of each cochlea was determined using the surface preparation technique. The audiometric and histological results were consistent within each group. A severe sensorineural hearing loss and hair cell loss was observed in all animals in the 147-dB group. The 137-dB group returned to normal hearing by 24 hours and had essentially normal cochleas (hair cell losses ≈1%–2%). However, the interaction effect could still be seen in the abnormally large values of TTS measured.
Internal-wave-induced acoustic fluctuations in a horizontally stratified medium
Authors: Jaffee R. J. , Porter R. P. , Spindel R. C.
Published: October 2005

Passage of an acoustic signal through an internal wave field results in the presence of amplitude and phase fluctuations at the receiver. The acoustic-internal wave interaction has been discussed previously using ray techniques [R. P. Porter, R. C. Spindel, and R. J. Jaffee, J. Acoust. Soc. Am. 56, 1426–1436 (1974)]. We report here on wave techniques describing the interaction phenomenon. The Rytov perturbation approach is applied to a horizontally stratified medium which is perturbed by the internal wave field. Statistical expressions for the acoustic fluctuations are obtained based upon a postulated internal wave model [C. Garrett and W. Munk, Geophys. Fluid Dynam. 2, 225–264 (1972)]. It is shown that for internal wavelengths comparable to acoustic ray cycle distances a resonant condition exists leading to large acoustic fluctuations. The validity and limitations of the perturbation technique applied to the horizontally stratified medium are discussed.
Power flow between strongly coupled oscillators
Authors: Gulizia C. F. , Price A. J.
Published: October 2005

The theory describing power flow between two sets of linearly coupled oscillators is reexamined for the case of arbitrary coupling strength. For simplicity, gyroscopic coupling is assumed and the equations of motion for two linearly coupled oscillators are solved using a Fourier transform technique which is found to be useful to increase the ease and elegance of the derivation as well as to retain an explicit frequency dependence in the solution. Some general assumptions are made on the shape of the Fourier transforms of the mechanical impedances, input forces, and the form of statistical independence. It is found that, as expected, the modal coupling coefficients are functionally dependent upon the strength of the coupling elements. As a limiting case, the result of Lyon and Maidanik [J. Acoust. Soc. Am. 35, 623 (1962)] can be obtained by frequency averaging the coupling coefficient derived in the present analysis. However, it is found that the radiation resistance can be obtained from the same equation as given by Lyon and Maidanik for weak coupling. The results of several experiments designed to show the effects of strong coupling are described. The results are in fair agreement with the theoretical predictions from the first part of this paper.
Lateral motions of a long towed array
Authors: Murphy D. A.
Published: October 2005

The lateral displacements of hydrophones in a long towed horizontal line array have been measured by using the phase differences of a received CW signal at the various hydrophones, The data were reduced using two-dimensional Fourier transforms. The spectrum of the motion was calculated, and it shows no differentiable peaks other than one at extremely low frequencies. The period of this motion for the case of a long array and slow tow is very long, but finite, The array maintains a readily measured decaying curvature due to a tow ship turn for a period of time which is proportional to the distance of the array center from the tow point and inversely proportional to the tow speed, It is concluded that measurements of towed array motions with short data samples can lead to erroneous conclusions.
Discriminability of modified time-reversed click pairs
Authors: Resnick S. B. , Feth L. L.
Published: October 2005

We recently proposed that time-reversed click pairs are discriminable when the less intense click is detectable in those pairs in which the less intense click occurs first (“L-M” pairs) but is undetectable in the time-reversed (“M-L”) pairs [J. Acoust. Soc. Am. 55, S31(A) (1974)]. The notion was tested in the present study by assessing the discriminability of modified click pairs. For the modified click pairs, the interclick intensity ratio (ΔI) in the M-L pairs was reduced relative to ΔI in the L-M pairs. Click-pair discriminability was determined for normal-hearing listeners using a 21 FC procedure. Unmodified time-reversed click pairs yielding high P(C) scores were presented on 80% of the trials; modified click pairs were presented on 20% of the trials. Preliminary results suggest click-pair discriminability is dramatically reduced by modifications which make the less intense click detectable in both the L-M and M-L click pairs.
TTS in man from a 24-hour exposure to an octave band of noise centered at 4 kHz
Authors: Melnick William
Published: October 2005

Ten adult males were exposed to a sound field consisting of an octave band of noise centered at 4 kHz for 24 hours at an octave band level of 80 dB. Seven of these men were also exposed to the same noise at 85 dB for 24 hours. Hearing thresholds were measured in one ear at 11 test frequencies from 250 to 10 000 Hz prior to, during, and after exposure. As in previous experiments with a 300–600-Hz noise band, TTS appeared to reach asymptote after 8 to 12 hours of exposure. Maximum asymptotic threshold shifts (ATS) occurred at 4 and 6 kHz. The magnitude of ATS for this sample of subjects was less than would be expected from previous studies. For the seven men who were exposed to both noise levels, the asymptote at 4 kHz was 9.7 dB from the 80-dB noise and 18.4 dB for the 85-dB exposure. ATS increased 1.74 dB per decibel increase in exposure, a growth rate similar to that reported earlier. Thresholds recovered to within 5 dB of pre-exposure levels by 24 hours and completely by 48 hours.
Analysis and synthesis of the EMG fine structure of lip muscles during speech
Authors: Cooker H. S. , Cary B. J.
Published: October 2005

Electromyographic activity from muscles involved in the elevation and depression of the lower lip was monitored through the use of concentric needle electrodes during the production of syllables initiated with bilabial stop-plosives. Lower-lip displacement and vocal output were monitored concurrently with the electromyography, and all data were recorded on an FM tape recorder. Selected segments of the data were computer-processed by means of a time domain analysis strategy utilizing Hanning Cosine Modulated (HCM) wave functions. Examination of HCM parameters for different muscles at different production rates was conducted to assess the effect of changing velocity on the EMG signal, By using an algorithm based on the derived HCM parameters, it was possible to synthesize rather precisely the EMG fine structure associated with a particular muscle at a particular production rate. The original and synthesized EMG signals are presented for comparison, and the effects of HCM parameter manipulation on the synthesized fine structure are demonstrated.
Noise in parametric receivers
Authors: Goldsberry Tommy G.
Published: October 2005

Interfering noise sources that limit the sensitivity of a parametric receiver were discussed at the last meeting of this Society [T.G. Goldsberry, J. Acoust. Soc. Am. 56, S41(A) (1974)]. The individual noise sources in an experimental parametric receiver have been measured to test the hypotheses presented in that paper. The predicted effect of these noise sources on sensitivity is compared to the measured performance of the parametric receiver. Factors that limited the sensitivity of the experimental parametric receiver are discussed. [This work was supported by the Office of Naval Research.]
Transmissibility of simply supported, rectangular, thin plates with mass, rib, or ring loadings
Authors: Ochs J. B.
Published: October 2005

The transmissibility across rectangular, simply supported, thin plates vibrating transversely has been measured experimentally through the frequency range 25–3025 Hz. Good success has been achieved in obtaining simply supported plate boundaries; the design of these followed directly from a preliminary study of several “simple supports” for long thin beams. Transmissibility has been measured across plates with concentrated mass loadings and with ten combinations of straight or circular rib loadings. In each case, the total added mass equalled the plate mass. Measurements were also made on plates coated by damping tile. Very favorable agreement between the experimental results and theory has been found in those cases where comparison could be made; namely, between the transmissibilities of unloaded plates, damped plates, and centrally mass-loaded plates [J. C. Snowdon, J. Acoust. Soc. Am. 56, 1177–1184 (1974)]. Choice of the most suitable mass or rib geometries for overall attenuation of transmissibility is discussed, together with choice of the most effective rib geometry with which to attenuate any one resonant peak. [Investigation supported by the Naval Sea Systems Command.]
Some dynamical problems of magneto-thermo-elasticity
Authors: Dökmeci M. Cengiz
Published: October 2005

We consider in this study a nonpolar, elastic, isotropic, homogeneous, and continuous finite medium. The medium is of finite electrical conductivity and is within a constant primary magnetic field. Hence the medium becomes deformed and an electromagnetic field is excited. Thus the solutions of two sets of equations should be examined: the magneto-thermo-elasticity equations in the domain occupied by the medium (interior problem) and the electrodynamics equations outside of the domain (exterior problem). First, the three-dimensional-equations of magneto-thermo-elasticity are reduced to the one-dimensional (for bars) and two-dimensional (for shells and plates) equations. The exterior and interior problems are jointly considered and a method of asymptotic integration [S. A. Ambartsumian, G. E. Bagdasarian, and M. V. Belubekian, PMM 35, 216–228 (1971); M. C. Dökmeci, Int. J. Solids Struct. 8, 1205–1222 (1972)] is employed in the formulation. A fundamental interaction process is thus constructed for shells and plates as well as for bars. It may incorporate as many higher-order effects as deemed necessary. The results are illustrated in detail in sample problems under small perturbations. [Work supported by the Turkish Office of Naval Research.]