bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustical Hazards of Children's “Toys”
Authors: Hodge David C. , McCommons R. Bruce
Published: September 2005

Measurements of impulse noises produced by four toy firearms are presented. It is suggested that these “toys” constitute a potential hazard to children's hearing.
Formation of Difference Patterns in Transducer Arrays with an Odd Number of Elements
Authors: Wilson Geoffrey L.
Published: September 2005

A modification of the Dolph-Chebyshef method may be employed to generate near-optimum shading coefficients for a difference pattern of an array consisting of either an odd or even number of elements.
Elastic Properties of NiTi as a Function of Temperature
Authors: Spinner S. , Rozner A. G.
Published: September 2005

Young's modulus, shear modulus, and internal friction of the intermetallic compound NiTi have been measured as a function of temperature from about −180° to 600°C, in the kilocycle-per-second range. Annealed and cold-worked specimens were used. All the specimens showed the same general pattern, with a minimum in elastic moduli occurring about 70°–140°C, depending upon the particular specimen, and a maximum in internal friction occurring some 50°C below the minimum in elastic modulus. Young's modulus was the same for all the specimens (694 kbar) within experimental error, but the shear modulus of the cold-worked specimens was more than 10% higher than that for the annealed specimens.
Directional Characteristics of Vibrating Circular Plates and Membranes
Authors: Laura Patricio A.
Published: September 2005

The sound field from a circular radiator set in a rigid and infinite wall has been investigated by several authors. Calculations are presented in this paper taking onto consideration the structural characteristics of the radiator. It is shown also that the functional representation of the normal velocity used by some authors for a “membrane source” corresponds actually to a “clamped-plate source.”
Numerical Studies of Elastic-Disk Contour Modes Lacking Axial Symmetry
Authors: Holland Richard
Published: September 2005

The eigenvalue problem for axially asymmetric contour extensional modes of thin elastic disks with planar isotropy has been solved numerically. This solution includes determination of the dimensionless eigenvalues and the associated particle-displacement eigenfunctions with normalization coefficients. Results are presented in tabular form for modes having angular index less than 10 and for values of Poisson's ratio between 0.25 and 0.50. The 68 modes of this class, which are graver than the fourth axially symmetric mode, have been considered. The resulting orthonormal modes are ideal for eigenfunction expansion (i.e., generalized Fourier series) solutions of elastic disks driven by axially asymmetric forces. Quantitative studies of axially asymmetric electroded piezoelectric disks also become feasible.
Vibrations of a Timoshenko Beam, Using Finite-Element Approach
Authors: Kapur Kanwar K.
Published: September 2005

The finite-element method for solution of problems in structural mechanics is extended to vibration of beams, including shear and rotary inertia effects. Use is made of a consistent mass matrix in conjunction with the corresponding stiffness matrix. The method is applicable to uniform and nonuniform beams with any boundary conditions. Excellent agreement with exact results has been obtained, even for a very coarse subdivision of the beam.
Graphical Method for Obtaining the Natural Frequencies of a Three-Degree-of-Freedom System
Authors: Wang Han-chung
Published: September 2005

An analogy between an undamped three-degree-of-freedom vibration system and a three-dimensional elastic body is discussed. The approximate natural frequencies of the system are obtained graphically using the Mohr circle technique, which is applied for determining the principal stresses of an elastic body.
Sound Transmission through a Finite, Closed, Cylindrical Shell
Authors: White Pritchard H.
Published: September 2005

The transmission of an acoustic wave through an infinite, homogeneous, isotropic cylinder has been derived to be a strong function of frequency and the angle of incidence between the axis of the cylinder and the incoming wave. From this analysis, two important characteristics are found: the ring frequency, where the wavelength of a longitudinal wave in the material is equal to the circumference, and the coincidence frequency, where the trace wavelength of the incident wave is equal to the bending wavelength in the shell wall. The transmission loss will take on minimum values at these two points. Measurements with 13 oct-band noise excitation of a closed cylindrical shell with l/d - 1.5 show the same gross features to be present and with additional effects of low-frequency resonances, but with very little angular dependence. The presence of stiffening corrugations and irregularities in the shell leads to a random-vibration field and allows methods developed for the transmission of random sound through flat panels to be used successfully for noise-reduction estimates.
Sound-Ranging Technique for Locating Supersonic Missiles
Authors: Rachele Henry
Published: September 2005

Mathematical formulations are developed that can be used with conventional sound-ranging data for determining a first approximation of a point on a trajectory of a vertically falling supersonic missile. The most interesting feature of the development is that it requires only a single four-microphone square array.
Conversion of Electromagnetic to Acoustic Energy by Surface Heating
Authors: Gournay Luke S.
Published: September 2005

The stresses that evolve in a thermally shocked liquid were examined. The magnitude and time duration of stress transients generated by a Q-switched ruby laser were measured in the absence of a phase change and compared with results calculated from a simplified thermodynamic model. It is shown that the model agrees with experimental data over a wide range of incident electromagnetic intensity and for large variations of liquid properties. Results are also presented to show the effect of liquid vaporization on the stress transients and the parameters associated with formation of a gas phase.
Temporary Threshold Shifts in Hearing from Exposure to Combined Impact/Steady-State Noise Conditions
Authors: Cohen Alexander , Kylin Bengt , LaBenz Paul J.
Published: September 2005

Temporary threshold shifts (ITS) in pure tone hearing acuity are reported for 15 subjects exposed in separate 15-min periods to taped impact sounds [played back at 124- to 127 dB peak sound-pressure level (SPL)], to three levels of filtered (75- tn 1200 cps) steady-state noise (90, 100, 110 dB SPL), and to combinations of the recorded impact sounds with each level of the steady-state noise. TTS's from all such exposures were typically small, with the largest shifts occurring in the 1000- to 3000 cps frequency range. When combined with 90- and 100 dB steady-state noise, the impacts caused less threshold shift than when presented alone. Such TTS reductions were believed due to the relatively greater ability of the steady-state noise to arouse and sustain the acoustic reflex with its consequent sound-attenuation effect. The addition of the 110 dB steady-state noise did not induce a similar result quite possibly because this exposure, by itself, caused threshold shifts equal to or exceeding those of the impact sounds. More-effective stimulation of the acoustic reflex was believed responsible for findings showing less TTS for combined impact/steady state noise than from exposure to just the steady-state component of the combination. Indirect measures of acoustic-reflex response [contralateral remote masking (CRM)] generally indicated that those ears with a strong reflex response show less noise-induced shift. Correlations between TTS from impact and from steady-state noise for the subject group indicated some degree of positive correspondence limited to frequencies of of 2000 cps and below and strongest for those subjects with a poor reflex response as shown by their CRM data.
On the Generation of Odd-Fractional Subharmonics
Authors: Dallos Peter J.
Published: September 2005

In chinchilla ears, between 1000 and 3000 Hz, the common one-half frequency subharmonic is not present. Instead, pairs of odd-fractional subharmonics are seen. These distortion components appear at threshold only in specific frequency relations with the fundamental. Above threshold, both the frequency and the magnitude of the subharmonic depend on the stimulus intensity. With direct mechanical stapes stimulation and with various probe-tone experiments, it was shown that the odd-fractional subharmonics originate in the inner ear. The phenomenon of subharmonic squelch effect was described.
Origin of Summating Potential
Authors: Johnstone J. R. , Johnstone B. M.
Published: September 2005

The relationship between sound and cochlear potentials is considered in the light of von Békésy's observations of movement of the cochlear partition and Davis' variable-resistance theory of hair-cell function. An equation is derived relating hair angle to basilar-membrane movement. The equation is φ = arcot (Yα+cotφ0) where φ is the hair angle and α is proportional to basilar-membrane movement. φ0 is the resting hair angle. Y is the ratio of the distance between basilar membrane and hair cell apex to the distance between tectorial membrane and hair-cell apex. It is shown that the sigmoidal shape of this function leads to a linear dependence of microphonics on sound intensity, generation of harmonics, and production of positive and negative summating potentials by inner and outer hair cells, respectively. The behavior of the cochlear potentials, including the effect of sound pressure in reversing summating potential polarity, effect of cochlear pressure changes, and reversal of summating potential polarity with anoxia, is also accounted for. A mechanical model of the organ of Corti, used to illustrate our theory, is described, together with results obtained from the model.
Measurement of Stapedial-Footplate Displacements during Transmission of Sound through the Middle Ear
Authors: Rubinstein M. , Feldman B. , Fischler H. , Frei E. H. , Spira D.
Published: September 2005

The frequency response of stapedial-footplate vibration during sound conduction was measured on fresh cadaver specimens. Specially designed and adapted instruments made these measurements possible at sound levels lower than those causing discomfort to living subjects (84 114 dB), and with a continuous frequency sweep between 100 cps and 10 kcps. The results show a similarity with the curves of subjective ear sensitivity, suggesting a dependence of the over-all sensitivity of the ear on the middle-ear frequency response. Linear increase of vibration amplitude with sound level was found to exist up to around 104 dB; above this sound level, there is a gradual limiting of the stapedial excursions. Speculations on energy transfer from the middle to the inner ear showed nearly optimal matching between them. The influence of the aging process of the specimens is discussed.
Efferent Inhibition of Auditory-Nerve Responses: Dependence on Acoustic-Stimulus Parameters
Authors: Wiederhold Michael L. , Peake William T.
Published: September 2005

Electrical stimulation of the crossed olivocochlear bundle in anesthetized cats reduces auditory-nerve responses (N1) if the acoustic stimuli are at low sound-pressure levels but does not produce detectable changes in neural responses for click stimuli more than 60 to 70 dB above visual-detection level for N1. When the sound-pressure levels of high-frequency (10 000-Hz) and low frequency (400-Hz) transient acoustic stimuli were matched according to a physiological criterion, the neural response to the high- frequency stimulus was reduced more by olivocochlear bundle stimulation than the response to the low-frequency stimulus. These result, suggest certain characteristics for the mechanisms which influence the activity of single auditory-nerve fibers.
Effects of Stimulus Content and Duration on Talker Identification
Authors: Bricker Peter D. , Pruzansky Sandra
Published: September 2005

Sixteen listeners attempted to identify the talker when listening to speech samples of varying duration and content. The samples, recorded by 10 different talkers, were of five types: excerpted vowels, excerpted consonant-vowel (CV) sequences, monosyllabic words, disyllabic nonsense words, and sentences. Identification accuracy improved directly with the number of phonemes in the sample even when duration was controlled. Stimulus-response matrices differed substantially between the two vowels ([a] and [i]) used in the vowel and CV samples: relative identifiability of the talkers, response preference, and error patterns were all found to depend on vowel type. Confusion matrices for a given vowel exhibit definite asymmetries. In a limited additional study, subsets of listeners made identifying responses with the tapes reversed; performance deteriorated on even the briefest excerpts. The results pose some difficulties for a model of talker-identification behavior based on attributes of voice quality.
Intense Ruby-Laser-Induced Acoustic Impulses in Liquids
Authors: Carome E. F. , Moeller C. E. , Clark N. A.
Published: September 2005

An experimental study has been made of the acoustic signals induced in liquids by the focused beam from a Q-spoiled ruby laser. Very intense acoustic impulses have been produced with laser pulses of less than 0.05 J total energy. These appear to be generated by dielectric breakdown and not associated with the hypersonic waves that may be produced simultaneously by stimulated Brillouin scattering. The observed impulses have peak pressures of approximately 500 atm and frequency components in excess of 2400 Mc/sec.
Pressure Radiated by a Point-Excited Elastic Plate
Authors: Feit David
Published: September 2005

The acoustic pressure radiated by an infinite elastic plate excited by a time-harmonic point force or moment is obtained. The expression is valid for frequencies above and below the coincidence frequency. Below coincidence the pressure pattern is relatively nondirective and, for all practical purposes, insensitive to structural damping. Above coincidence, the pressure pattern becomes directive, and the peak pressures can be significantly reduced by structural damping.
Wave Interaction of a Viscoelastic Medium with an Elastic Cylindrical Shell
Authors: Finlayson Fred C. , Shulman Yechiel
Published: September 2005

The problem of the wave interaction between a linear viscoelastic medium and a thin cylindrical shell imbedded within it is solved for the case of a uniform harmonic stress input applied to the shell. The medium is characterized by the complex modulus representation for the shear modulus and is regarded as being elastic in bulk. The close agreement of this representation with experimental evidence for high polymers renders its use for this class of problems more desirable than the two- or three parameter mechanical models. Exact solutions for the displacement and stress response of the shell and medium are obtained. The results indicate that the nearfield response is approximately inversely proportional to the radial distance and is insensitive to frequency at low frequencies, but increases at high frequencies. The far field amplitude in creases with frequency and, in addition to the inverse-square-root variation with radial distance, characteristic of elastic media, it contains a strong exponential decay.
Nonlinear Resonance in Stretched Strings with Viscous Damping
Authors: Anand G. V.
Published: September 2005

The phenomena of amplitude jumps and nonplanar oscillations, which are characteristic features of non-linear resonance in stretched strings, have been studied in detail, taking the effect of damping into account. Expressions for the resonance frequency and amplitude, and the frequencies and amplitudes at which the jumps occur, have been obtained; and it has been shown that the resonance frequency is not a constant of the system but increases with the driving force. Finally, it is established that, in the presence of damping, (1) nonplanar oscillations exist only if the driving force φ exceeds a certain critical value, φu; (2) over a small interval of the driving force φj′; > φ > φw the nature of the downward jump is qualitatively different from the (normal) downward jump occurring for values of φ greater than φj′; (3) if φ, lies in the interval φw > φ > φj, jump phenomenon is exhibited even though the oscillations are planar at all frequencies; and (4), if φ < φj, the response is essentially linear in character. In Appendix A, it has been established that, if φ > φw, upward jump in amplitude is always accompanied by a transition to nonplanar motion unless the damping is very heavy.
Reply to “Comments on ‘Static and Dynamic Transmission Losses of Partitions’ ” [T. J. Schultz and B. G. Watters, J. Acoust. Soc. Am. 35, 2023 (L) (1963)].
Authors: Raes Auguste C.
Published: September 2005

This reply presents a brief critique of the statements made in a Letter to the Editor.
Interaction Radiation Resistance and Reactance Measurements for Two Small Transducers at an Air Water Surface
Authors: Stumpf F. B. , Crum L. A.
Published: September 2005

Results of measurements are presented for the interaction radiation resistance and reactance for a linear array of two small magnetostrictive-stack transducers at an air-water surface.
Unique Directional Reflectors for Omnidirectional Underwater Acoustic Transducers
Authors: Crews Arthur A. , Erath Robert L.
Published: September 2005

Directional reflectors for use with commercial omnidirectional underwater acoustic transducers are described herein. The reflectors are easy to construct, inexpensive, and exhibit none of the ringing characteristics found so frequently with metallic reflectors.
Fish as a Possible Cause of Low-Frequency Acoustic Attenuation in Deep Water
Authors: Weston D. E.
Published: September 2005

A possible cause of the anomalously high deep-water acoustic attenuation in the region from 50 cps to 5 kcps is scattering and absorption by bathypelagic fish having swim bladders. But calculation shows that the members of batbypelagic fish are normally about two orders of magnitude too low so, although out the main cause, they might sometimes contribute significantly. In comparison, shallow-water attenuation shows important effects caused by fish.
HUMAN HEARING UNDER WATER: ARE THINGS AS BAD AS THEY SEEM?
Authors: Feinstein Stephen H.
Published: September 2005

This paper questions the results of earlier studies that sound that the submerged diver loses the ability to localize sound. Preliminary data indicate that a diver can localize a sound source that is a maximum of 10° off the midline and in front. Further data are presented that show that a diver in a reverberant tank is able to hear the effect of a highly reflective (air-Plexiglas) target placed 1 ft in front of a speaker emitting broadband clicks at the role of 27/sec. Demonstration of auditory localization and echo detection by a submerged diver should raise same questions about the whole notion of degradation of the auditory function in the submerged human ear.
Nonlinear Oscillations of a Bubble
Authors: Woo Seng H. , Paslay Paul R.
Published: September 2005

The oscillation of a gas-filled bubble in a fluid has been studied previously by several approaches. In general, the fluid is considered incompressible, and the gas is assumed to behave as a linear spring. Surface tension and gravity effects are usually ignored. Radiation losses of such bubbles are often determined experimentally. The analysis presented here includes surface-tension effects. The gas considered is a perfect gas and the fluid an inviscid compressible fluid. The field equations for the fluid are linearized so that the nonlinearities of the problem arise from the following two sources. (1) The boundary condition at the fluid-gas interface has a time dependent radius; and (2) the adiabatic pressure-volume relation for the gas is nonlinear. Free oscillations of the bubble are studied. In order to induce free motion, the gas-fluid interface of the bubble is considered to be initially at rest and then a pulse of pressure is delivered to the interior of the bubble. The ensuing motions are analyzed by a numerical integration scheme. Numerical results are presented for air bubbles in water. The most remarkable result is that the frequency of oscillation is essentially independent of amplitude for the cases studied. The results further indicate, as one would expect, that the numerical integration scheme used here is not practical for the determination of the radiation damping. When the small radiation damping is neglected, the motion becomes periodic and—for cases studied—a harmonic analysis of the pressure field was performed that shows that the radius and pressure variations can differ appreciably from the sinusoidal waves predicted by the linearized theory.
Release of Masking for Speech through Interaural Time Delay
Authors: Carhart Raymond , Tillman Tom W. , Johnson Kenneth R.
Published: September 2005

Interference with binaural intelligibility of spondaic words produced by continuous white noise and of monosyllabic words produced by both continuous and modulated white noise as well as connected speech (single talker) was studied under a variety of interaural listening conditions. Performance during homophasic (N0S0) and antiphasic (NπS0) listening was compared with that achieved under conditions involving various interaural time differences of the noise and/or the speech. These time differences ranged from 0.1 to 0.8 msec. Several signal-to-masker ratios were employed, but for the conditions involving modulated noise, only two modulation rates (4/sec and 100/sec) and a single magnitude of modulation (14 dB) were used. Transition from homophasic to antiphasic listening produced masking-level differences (MLD's) of about 7 and 4 dB for spondees and monosyllables, respectively. The MLD's produced by varying the interaural timing of either speech or noise increased systematically as the time differences were increased within the range studied here, but they never exceeded those for antiphasic listening and were usually appreciably smaller. As gauged by performance under 0.4- and 0.8-msec interaural time delay, the MLD for monosyllables was the same regardless of whether the time difference was applied to the masker or the speech. Furthermore, the MLD produced by simultaneous but opposing interaural time differences (masker leading in one ear and speech in the other) did not exceed the antiphasic MLD, even when the aggregate timing discrepancy between the two signals reached 1.6 msec. Some implications of these findings are discussed.
Frequencies Dominant in the Perception of the Pitch of Complex Sounds
Authors: Ritsma Roelof J.
Published: September 2005

This paper deals with measurements carried out with pulsive signals to determine the spectral region associated with dominant pitch perception. The stimulus consisted of the sum of (1) a low-frequency band of a unipolar pulse train with fundamental frequency f0 (or f0+Δf) and upper cutoff frequency fe and (2) a high-frequency band of a unipolar pulse train with fundamental frequency f0+Δf (or f0) and lower cutoff frequency fe. In the experiments f0 was 100, 200, and 400 Hz, respectively; Δf/f0 was either 3% or 6%; and over-all sensation level was between 30 and 50 dB. When the fundamental frequencies were interchanged, a pitch change “up” or “down” was heard, depending on the “crossover” frequency fe. For fe larger than the sixth harmonic, the low-frequency band always dominated the pitch percept. Changing the sensation level of the low-frequency band with respect to the higher-frequency band, the minimum sensation level for dominant pitch perception was determined. It was found that, for a given fe, the low band tended to dominate the pitch perception as long as its amplitude exceeded a minimum absolute level. Dominance was found to be independent of Δf. By selectively limiting the number of components in the low-frequency band, the spectral region dominant for the perception of pitch was determined more precisely. This spectral region covered the frequency band consisting of the third, fourth, and fifth harmonics for signals with fundamental frequencies in the range of 100–400 Hz.
Acoustic Radiation from a Driven Infinite Plate Backed by a Parallel Infinite Baffle
Authors: Maidanik G.
Published: September 2005

The far-field acoustic pressure generated by an infinite plate driven by a point and a line force are computed. This paper constitutes an extension of previous computations [G. Maidanik and E. M. Kerwin, Jr., J. Acoust. Soc. Am. 40, 1034–1038 (1966)]. The extension is in the sense that the plate considered here is backed by a third medium that is terminated by a parallel infinite baffle. It is shown that when the absolute value of the acoustic reflection coefficient of the baffle approaches unity, the presence of the baffle may substantially affect the far-field acoustic pressure. The far-field acoustic pressure when the spaces in the front and the back of the plate are occupied by different fluid media is briefly considered.
Acoustic Radiation from a Driven, Coated Infinite Plate Backed by a Parallel Infinite Baffle
Authors: Maidanik G.
Published: September 2005

The far-field acoustic pressure generated by an infinite plate driven by a point and a line force are computed. This paper constitutes an extension of previous computations [G. Maidanik, J. Acoust. Soc. Am 42, 27–31 (1967)]. The plate considered in this paper is covered uniformly and completely by a compliant coating which is applied in turn to the front and back of the plate. The formalism accounts for different fluids' occupying the space in front of the plate and in the cavity back of the plate.
Acoustic Nonlinearity of an Orifice
Authors: Ingard Uno , Ising Hartmut
Published: September 2005

The acoustic nonlinearity of an orifice in a plate has been investigated by measuring simultaneously the oscillatory flow velocity in the orifice and the acoustic-pressure fluctuations producing the flow. The relation between the pressure and velocity amplitudes, which is linear at sufficiently low pressures, is found to approach a square-law relation at large velocity amplitudes. By evaluating the phase relationship between the fundamental harmonic components of pressure and velocity, the acoustic-orifice impedance is determined. In the square-law region of the pressure/velocity relation, the resistive component of the orifice impedance dominates and is proportional to the velocity amplitude. This method of measurement, which is particularly useful at high amplitudes, is supplemented by measurements of sound transmission and frequency response of the orifice plate so that an impedance curve can be constructed over an extended range of amplitudes. An analogous program of measurements has been carried out to study the influence of a superimposed steady flow on the acoustic-orifice impedance. Finally, as an application of the results obtained, the absorption characteristics of resonator absorbers for high-intensity sound are discussed.
Elastic Constants of Filamentary Composites with Rectangular Symmetry
Authors: Behrens Ernst
Published: September 2005

Dispersion relations for the propagation of elastic waves in filamentary periodic composites with rectangular symmetry are obtained for wavelengths that are long as compared with the intercomponent spacings. This yields averaged elastic constants of the material in terms of geometrical data and the elastic constants of the constituents. General averaging rules are established for all nine independent elastic constants. These rules are valid for any spatially varying elastic moduli and density with rectangular symmetry in the elementary cell. In the special case of a square lattice, the formulas are evaluated in the Wigner-Seitz approximation. For two constituents, this gives explicit expressions for all six independent elastic constants.
Sound Propagation in Lamellar Composite Materials and Averaged Elastic Constants
Authors: Behrens Ernst
Published: September 2005

Dispersion relations for the propagation of elastic waves in a lamellar periodic composite are obtained for wavelengths that are long as compared with the intercomponent spacings. This yields exact explicit expressions for the complete set of five independent, elastic constants of the material, in terms of geometrical data and the elastic constants of the constituents. The expressions are valid for any spatially varying elastic moduli and for density-showing periodic structure and mirror symmetry within the elementary cell.
Numerical Solution for Transient Scattering from a Hard Surface of Arbitrary Shape—Retarded Potential Technique
Authors: Mitzner K. M.
Published: September 2005

The problem of transient scattering from a hard surface S reduces to the solution of an integral equation for the potential at S. To allow numerical solution, S is divided into K zones, on each of which the potential is assumed constant, and time is also divided into discrete intervals. These approximations lead to a set of K algebraic equations relating the present values of the potential to the retarded values and to the incident field. When the zoning is done properly, each equation involves only one present value, which can therefore be calculated explicitly from the retarded values. It is important to compute the coefficients in the K equations accurately. This is accomplished by a numerical technique which takes into account the curvature of the zones and the variation in time retardation across zone. For scattering from a sphere, results agree very well with those obtained by separation of variables.
Auditory Sensitization
Authors: Deatherage Bruce H. , Henderson Donald
Published: September 2005

In three experiments, we have attempted to demonstrate the phenomenon of sensitization. We believe that we have succeeded. A brief high-frequency tone was added to a low-frequency carrier at various phases of the low frequency. Classical threshold was shifted up when the stimulus was added between 200° and 360°, and threshold was shifted down between 0° and 180°. This effect was greatest when the low frequency was at −5 dB sensation level (SL). At 20 dB SL the effect was partially obscured by masking.
Relation of Induced Tinnitus to Physical Characteristics of the Inducing Stimuli
Authors: Loeb Michel , Smith Richard P.
Published: September 2005

After observers were exposed to intense pure-tone and broad-band acoustic stimuli, their temporary threshold shifts were measured, and they were asked to match the pitch of any resulting tinnitus by manipulating the frequency of an adjustable low-level pure tone in the opposite ear. It was found that both the frequency of tinnitus and the frequency of the tone used for the pitch match increased as the frequency of the traumatic stimulus increased, but maximum loss frequency and tinnitus frequency did not coincide. Although the observers were quite reliable in their judgments of tinnitus elicited by a stimulus, interobserver variability was considerable.
Beats of Mistuned Consonances
Authors: Plomp R.
Published: September 2005

Two simultaneously sounding simple tones of M and N cps, respectively, with M:N slightly different from m:n (both small integral numbers) may give rise to a beat sensation with mN − nM beats per second. For the case m = 1, these beats are usually explained as resulting from harmonics created in the ear by distortion. Experiments indicated, however, that for m ≠ 1 secondary tones cannot be the main origin of these beats because the beat sensation does not disappear when bands of noise are introduced in the frequency ranges around possible harmonics and combination tones. Other experiments in which, for a constant lower tone M, the sound-pressure level (SPL) of the higher tone N for most distinct beats was determined showed that this SPL decreases gradually for increasing frequency of N, irrespective of frequency ratio. Moreover, it was found that the beats for 200+601 cps manifest themselves in a weak tone sensation with a pitch shifting periodically in a sawtoothlike manner between about 610 and 730 cps. These experimental results suggest that, also for the case 1:n, the beats are not due to combination tones or aural harmonics but are related to periodic variations in the waveform of the overlapping vibration patterns along the basilar membrane, giving rise to corresponding variations in the time pattern of the nerve impulses.
Boundary Wave-Vector Filters for the Study of the Pressure Field in a Turbulent Boundary Layer
Authors: Maidanik G. , Jorgensen D. W.
Published: September 2005

A proposal for constructing a boundary wave-vector filter is made. The wave-vector filter consists of a flush-mounted pressure transducer system. The elements and characteristics of the system are discussed. The manner in which the system can be employed to study the nature of the boundary pressure field in a turbulent boundary layer is discussed.
Corrections for Attenuator Transient Effects to Data on Self-Recorded Audiometric Threshold of Normal-Hearing and High-Tone Deaf Persons
Authors: Coles R. R. A. , Rice C. G.
Published: September 2005

Stud-type attenuators in a widely used model of self-recording audiometer are apt to be associated with transients and intermittencies in the intensity/time envelopes of their acoustic output. These have been shown to result in more acute threshold measurements in normal-hearing subjects, and the effect is greater at the higher frequencies in persons with noise-induced hearing loss. Correcting for the effect of these transients results in good agreement between the authors' earlier data [J. Acoust. Soc. Am. 39, 1185–1187 (1996)] on normal threshold of hearing and current proposals for application of ISO Recommendation 389 to audiometers using TDH-39 earphones calibrated on 9-A couplers.
Cavitation Detection: The Use of the Subharmonics
Authors: De Santis P. , Sette D. , Wanderlingh F.
Published: September 2005

Ultrasonic cavitation in liquids gives rise to a sound oscillating field at a frequency one-half of the ultrasound-driving frequency. The appearance of such a subharmonic may be used to detect the cavitation. The authors investigate experimentally such a possibility.
Scattering of Acoustic Waves by a Penetrable Prolate Spheroid. I. Liquid Prolate Spheroid
Authors: Yeh C.
Published: September 2005

This is the first of a series of reports on the scattering of waves by a penetrable prolate spheroid. In this letter, the exact solution of the scattering of acoustic waves by a liquid prolate spheroid is obtained. Results are given in terms of the spheroidal functions. It is found that each expansion coefficient of the scattered or transmitted wave is coupled to all coefficients of the series expansion for the incident wave, except when the spheroid degenerates to a sphere. Detailed numerical computations for the radiation patterns of the scattered wave are carried out for a sphecific example. It is found that, in general, the radiation patterns for the scattered waves are more directional and possess more side lobes as the prolate spheroid becomes more elongated.
Acoustic Characteristics of Black Moshannon Lake Bottom
Authors: Ruff George A.
Published: September 2005

Standing-wave measurements made at the Ordnance Research Laboratory's Black Moshannon Calibration Station show that the water-bottom interface acts as a pressure-release boundary over the frequency range of 100 to 800 Hz.
Derivative of Travel Time with Respect to Source Angle for a Layer of Arbitrary Sound Speed Gradient
Authors: Stuart J. D.
Published: September 2005

An expression previously obtained for the rate of change of travel time, with source angle for a ray in a layer of constant-sound-speed gradient, is shown to be valid for any sound-speed gradient that is dependent upon the depth only.
Contradiction Concerning Shallow-Water Sound Attenuation
Authors: Weston D. E.
Published: September 2005

For medium-to-long ranges in shallow water, and for frequencies above about 100 cps, energy is still present in at least the first two normal modes. The observed transmission laws cannot then be explained, as has been usual, by summing the normal modes with separate attenuations due to the boundary losses. The probable explanation is the presence of an enhanced body attenuation, possibly due to bladder fish.
Auditory Continuity Effects as a Function of the Duration and Temporal Location of the Interpolated Signal
Authors: Elfner Lloyd F. , Homick Jerry L.
Published: September 2005

The present experiment employed 20 college students who demonstrated an ability to make determinations of interruption or continuity in a random noise signal that alternated with a tonal burst. The primary purpose of this experiment was to investigate the effects of the duration the temporal location of the interpolated signal on the perception of continuity under monaural presentation. The effect of frequency of the interpolated tone was also evaluated. The results showed that the perception of continuity in the noise was affected by both the duration and frequency of the interpolated tonal signal. The location of the interpolated signal had no significant differential effect on continuity thresholds.
Focusing of Aperiodic Waves in a Linear Viscous Medium
Authors: Dunn H. Searl , Dove William G.
Published: September 2005

The focusing of waves resulting from an idealized explosion—for example, the bursting of a spherical balloon—is examined in a viscous medium using the linearized equations of fluid dynamics. As expected, the structure of the viscous solution closely resembles that of the inviscid solution, the major difference being that discontinuities permitted by the inviscid theory are replaced by rapid but smooth transitions. It is found that if p0 denotes the initial overpressure contained within a sphere of radius R, the maximum pressure gain due to the focusing effect is approximately |p/p0| ≈ (R/l)12, where p is the pressure at the center of the sphere and l is the mean free path in the gas being considered.
Radiative Attenuation of Sound By CO2 and H2O
Authors: Kyle Thomas G.
Published: September 2005

The attenuation of plane sinusoidal acoustic waves due to the electromagnetic radiative properties of the 15-μ band of carbon dioxide and the 6.3-μ band of water vapor have been calculated for a wide range of acoustic wavelengths. These bands are found to be less important than the 25-μ band of water at short wavelengths, but more important than the latter at very long wavelengths.
Encoding of Stimulus Frequency and Intensity by Cat Superior Olive S-Segment Cells
Authors: Tsuchitani Chiyeko , Boudreau James C.
Published: September 2005

S-segment units exhibit definite absolute thresholds. Cells with similar characteristic frequency (CF) have similar thresholds. Stimulus intensity increases elicit monotonic increases in spike output up to a limiting plateau. The number of spikes at plateau is highly correlated with the dynamic range over which increases are seen. Stimulation with tones higher in frequency than the CF results in lower plateaus and smaller dynamic ranges. Only a limited band of frequencies can maximally stimulate a cell within normal intensity ranges.
Predicting Binaural Gain in Intelligibility and Release from Masking for Speech
Authors: Levitt H. , Rabiner L. R.
Published: September 2005

A simple, approximate procedure for predicting binaural gain in intelligibility and release from masking for detection of speech in broadband Gaussian noise is presented. The procedure assumes that the effect of binaural processing in the auditory system can be adequately represented by a frequency-dependent reduction in the level of the masking noise. The magnitude of this reduction is derived from data on release from masking for tones. Predictions of intelligibility are based on the Articulation Index as computed for the equivalent masking noise. It is predicted that the binaural gain in intelligibility for speech in white noise is greatest at low intelligibility levels, decreasing to about 3 dB at high intelligibility levels. The relative importance of low- and high-frequency interaural phase opposition in producing a binaural gain in intelligibility depends on the signal-to-noise (S/N) ratio. Low-frequency interaural phase opposition is of greater importance at low S/N ratios. Release from masking for detection represents a limiting case, the binaural gain being roughly 13 dB and dependent primarily on interaural phase information below about 500 Hz. Predictions based on this procedure are fairly consistent with data obtained in an earlier experiment. More data are required, however, for an adequate assessment of the technique. The implications for practical binaural systems are discussed.
Number of Pulses Required for Minimal Pitch
Authors: Pollack Irwin
Published: September 2005

The number of pulses required for minimal pitch was determined. For pulse intervals longer than 1 msec, appromixately a constant number of pulses is required: about three. For pulse intervals shorter than 1 msec. approximately a constant duration is required, about 3 msec. The results are in close agreement with findings for the click pitch of pure tones.
Flush-Mounted Pressure Transducer Systems as Spatial and Spectral Filters
Authors: Maidanik G.
Published: September 2005

Analysis of the responses of a flush-mounted transducer system to the pressure field in a turbulent boundary layer and to the boundary pressure field induced by an incident plane acoustic wave is formulated and discussed. The transducer system is considered as a spatial and a spectral filter. The properties of the filters are defined and illustrated for the case where the system consists of nominally identical transducers. The analysis is limited to geometries where the centers of the transducers are regular y placed at the centers of a plane rectangular grid. Time delays between transducers are allowed for in this analysis.
Calculation of the Nearfield Pressure Induced by Vibrating Circular Plates
Authors: Miner George W. , Laura Patricio A.
Published: September 2005

This paper deals with the determination of the nearfield pressure distribution induced by a circular radiator set in an infinite, plane, rigid baffle. Calculations are made in the present study for two deformable radiators (a clamped plate and a membrane or simply supported plate) and for a rigid piston. It is shown that the nearfield pressure distribution for the clamped and simply supported plate radiators differs greatly from the distribution obtained in the case of a rigid piston. In light of these considerations, the analysis and data presented in this paper could prove useful in the design of acoustic transducers.
Ultrasonic Phase Velocity by the Pulse-Echo-Overlap Method Incorporating Diffraction Phase Corrections
Authors: Papadakis Emmanuel P.
Published: September 2005

The pulse-echo-overlap method for ultrasonic time-delay measurements is reviewed. In this method, pairs of echoes are compared by driving the x axis of a viewing oscilloscope at a frequency equal to the reciprocal of the travel time between the echoes. A method for choosing the correct cyclic overlap for the rf within the echoes is given. Utilization of the proper cyclic overlap permits the accurate measurement of ultrasonic phase velocity. When corrections for the phase advance due to ultrasonic diffraction are applied to the travel times between various pairs of echoes, the accuracy of the average round-trip travel time is improved. Experimental verification of this is presented for longitudinal waves in isotropic materials and in the pure mode directions in cubic crystals. Delay times are accurate to 0.2 nsec or better.
Underwater Hearing Thresholds in Man
Authors: Brandt John F. , Hollien Harry
Published: September 2005

The audibility threshold performance of the human ear submerged in water at ear depths of 12 and 35 ft was compared to its performance in air. Threshold SPL's at 125, 250, 500, 1000, 2000, 4000, and 8000 Hz from five male and three female divers wearing open-circuit SCUBA equipment were obtained by the Békésy technique. Differences between water and air conduction thresholds ranged from 18 dB SPL re 0.0002 μbar at 125 Hz to 56 dB at 8000 Hz. Underwater thresholds ranged between 58 and 74 dB SPL, with maximum sensitivity around 500 Hz. Maximum sensitivity for air conduction thresholds was obtained at 2000 Hz. Slightly higher thresholds were obtained at the 35-ft ear depth than at the 12-ft depth. Tentatively, the data suggest the importance of bone-conduction mechanisms in underwater hearing. However, it is apparent that further research must be carried out before it will be possible to predict the character and mechanism of the human ear submerged in water.
Instrumentational Rôle in the Observation of Geoacoustical Phenomena from Artificial Sources
Authors: Fehr Uri
Published: September 2005

Many physical principles have been applied to transform atmospheric pressure fluctuations of 1 sec and longer into electrical signals for the purpose of monitoring infrasonic signals. A survey of some infrasonic sensors is taken, with calibration and testing of several sensors at the UCLA calibration facility. An attempt was made to define the capabilities of each available sensor. Several experiments are described, which include the monitoring of static and dynamic firing of rockets, as well as the monitoring of explosions. The difficulties in interpretation of data are explained in relation to various instruments, taking into account wind effects, ground vibrations (observed by magnetometers), natural pressure fluctuations, and other phenomena producing noise at the frequency range of interest.
Interaction of Light and Ultrasonic Surface Waves
Authors: Mayer Walter G. , Lamers Guillermo B. , Auth David C.
Published: September 2005

The intensity distribution in the orders of a light-diffraction pattern produced by the interaction of a progressive ultrasonic surface wave and a monochromatic light beam is calculated. The amplitude of the surface wave is determined from the light-intensity distribution in the diffraction pattern. The spacing of the diffraction orders is related to the surface wave velocity and the angle of light incidence.
Ultrasonic-Velocity Measurements in Water at Pressures to 10 000 kg/cm2
Authors: Holton Gerald , Hagelberg M. Paul , Kao Samuel , Johnson Walter H.
Published: September 2005

Measurements of the velocity of ultrasonic pulses in water are presented for pressures up to about 10 000 kg/cm2 and for temperatures up to 80°C. Coefficients obtained from least-squares polynomial fittings of the data are also given, together with an analysis of the reliability and reproducibility of the experimental results.
Extensional Waves in Elastic Bars of Rectangular Cross Section
Authors: Medick Matthew A.
Published: September 2005

A one-dimensional approximate theory is derived that accounts for the first eight modes of propagation of extensional waves in uniform, isotropic, linear elastic bars of rectangular cross section. The theory provides an optimal quadratic approximation to the lateral spatial dependence of the three-dimensional bar response. Applicable to motions in bars of arbitrary rectangular section, it is possible to predict bar responses that are neither plane stress nor plane strain, but are transitional between the two. The relation of bar to plate theory is established, and an identification of bar and plate modes is proposed. Discussion of dispersion of harmonic waves is limited to bars of square section. Typical spectra are given, and their variation with Poisson's ratio is established.
Acoustic Field Generated by a Vibrating Boundary. I. General Formulation and Sonar-Dome Noise Loading
Authors: Kuo Edward Y. T.
Published: September 2005

The theories developed by Rayleigh, Marsh, and Kuo are applied to the problem of determining the acoustic field generated by a vibrating boundary. A special case, the noise field generated by a vibrating sonar dome, is formulated and solved. An investigation performed by White is identified as a special case of the general formulation. This general formulation is such that a vast number of varied problems can be solved.