bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Intersignal Interval on the Human Auditory Evoked Response
Authors: Nelson David A. , Lassman Frank M.
Published: September 2005

Average evoked responses were recorded from human vertex in response to tone pulses presented at intersignal intervals (ISI) ranging from 0.25 through 10 sec. Tone pulses were 20 msec in duration with 20-msec rise and decay times. Frequencies investigated were 500, 1000, and 2000 Hz. Response amplitude was found to be a linear function of log10ISI. Response latency did not change significantly with ISI, except perhaps in component N2 of the response, which appeared to increase in latency as ISI increased. These relations obtained regardless of frequency.
Submicroscopic Displacement Amplitudes of the Tympanic Membrane (Cat) Measured by a Laser Interferometer
Authors: Tonndorf Juergen , Khanna Shyam M.
Published: September 2005

A laser interferometer, designed and constructed in this laboratory, was evaluated with respect to its applicability to measurements of amplitudes and phases in the ear. The instrument measures continuously up to a maximal amplitude of 0.92×10−5 cm, and higher at selected points. With respect to vibrations of the tympanic membrane, measured in an open sound field, the vibration isolations of the instrument was ample. The prevailing S/N ratio made it convenient to routinely measure amplitudes of 1 × 10−7 cm in living animals. At low frequencies, this corresponds to SPL's of approximately 60 dB. In fresh cadavers, however, while there was no immediate change in the magnitude of the responses, readings were extended to 1 × 10−9 cm, owing to the absence of pulse and breathing, giving a dynamic range of 80 dB. In all experiments, repeatability was excellent, and between-animal variations were low. The resulting transfer characteristics obtained in living animals, with the tympanic bulla closed, was generally similar to those obtained earlier, with some noted exceptions. The amplitude curve failed to show the slight hump around 1 kHz found earlier. The phase curve was much more complex than earlier ones and cannot be approximated by the assumption of simple network models.
Laser Interferometer for the Measurement of Submicroscopic Displacement Amplitudes and Their Phases in Small Biological Structures
Authors: Khanna Shyam M. , Tonndorf Juergen , Walcott W. W.
Published: September 2005

An interferometer is described. It is designed for measurements of submicroscopic displacement amplitudes of small biological structures in living animals. Its output is frequency independent. The instrument may be used for measuring: (1) absolute displacement amplitudes as low as 3 × 10−10 cm between 20 and 20 000 Hz; (2) phase angles of the displacements with respect to that of the applied sound signals; (3) transient responses of the vibrating structure. Theory of operation is discussed. Fabrication of microscopic mirrors and construction details of the interferometer are given. Experiments performed with the aid of an earphone as a vibrating object are included to show the characteristics of the interferometer. Calibration is precise (within 1 dB) and repeatability is excellent, both with respect to amplitude (within 1 dB) and phase (within 5°). Experiments on living animals and cadavers, giving amplitude and phase data, will be included in a separate paper.
Effect of Speaking Rate on Diphthong Formant Movements
Authors: Gay Thomas
Published: September 2005

Duration and formant frequency measurements of the five diphthongs, /ɔɪ,aɪ,aʋ,eɪ,oɪ/, were made for three conditions of speaking rate. Results indicate that onset target position and second-formant rate of change are fixed features of the diphthong formant movement, while offset target positions are variable across changes in duration. Other measurements show that increased diphthong duration due to the presence of a following voiced consonant is accomplished by longer steady-state targets for /ɔɪ,aɪ,aʋ/ and longer glide durations for /eɪ,oʋ/. The data provide a basis for an articulatory description of diphthong production.
Speaker Authentication and Identification: A Comparison of Spectrographic and Auditory Presentations of Speech Material
Authors: Stevens K. N. , Williams C. E. , Carbonell J. R. , Woods Barbara
Published: September 2005

Speaker authentication and identification were examined for two different methods of presentation of the speech material: (1) speech samples presented aurally through headphones, and (2) speech samples presented visually as conventional intensity-frequency-time patterns, or spectrograms. Two kinds of experiments were carried out: (1) a series of closed tests in which there was a library of samples from eight speakers, and test utterances were known to be produced by one of the speakers; and (2) a series of open tests in which the same library of eight speakers was used, but test utterances may or may not have been produced by one of the speakers. The results for the closed tests indicate that, after about 4 h of exposure to the test situation, the percent error in identification of speakers from isolated speech samples (words or phrases) is about six percent for aural presentation and about 21% for visual presentation. These scores depend upon the talker, the subject, and the phonetic content and duration of the speech material. For the open visual tests, appreciable numbers of false acceptances (incorrect authentications) were made. The results suggest procedures that might be used to minimize error scores in practical situations.
Identification of Speaker Sex from Isolated, Whispered Vowels
Authors: Schwartz Martin F. , Rine Helen E.
Published: September 2005

The results of this study reveal that Listeners are able to identify speaker sex from isolated productions of whispered vowels.
Lumped-Element Transmission-Line Analog of Sound in a Viscous Medium
Authors: Szabo Thomas L.
Published: September 2005

Interest in the transient of a wave in a viscous medium sparks the idea for a transmission-line analog of the viscous wave equation. For convenience, lumped elements are selected by the application of transmission-line-and-filter theory to simulate the transmission-line analog. Practical components for the model introduce additional parameters that cause the model to be better described by a higher-order, more general wave equation. Parameter choices are made to minimize the unwanted differences between the more realistic wave equation for the model and the viscous wave equation. The differential equation describing the actual model seems to have no easily attainable solution. However, a modified form of Blackstock's solution to the viscous wave equation is presented as a solution to a special case of the differential equation describing the actual model. Tone bursts injected into the completed model clearly show the presence of a precursor and a “postcursor.” Comparisons of the waveforms obtained experimentally and those predicted by the modified solution are shown and discussed.
Audience and Chair Absorption in Large Halls. II
Authors: Beranek Leo L.
Published: September 2005

Three alternate methods for considering the absorbing power of audience seating areas in the calculation of reverberation time in concert halls are treated. The absorption of audience seating, unoccupied and fully occupied, is expressed in terms of (1) equivalent sound-absorption coefficient αeq, (2) absorption per unit floor area (with edge corrections), αT, and (3) absorption per person aT. Recent data by Meyer, Kuttruff, and Roy, by Kosten, and by Kath and Kuhl are integrated with the author's data to yield new tables of αeq, αT, αS, αR, aT, and aS, where αR is the absorption coefficient of the nonseated areas of a hall, and αS and aS are the absorptions of unoccupied seating on a per-unit area and per-seat basis, respectively. The data show that total audience absorption increases in direct proportion to audience area (uniform distribution of persons and well-upholstered seats assumed), nearly independently of persons in the area. The halls studied have a range of seating densities from 5 to 8 sq ft of floor space per person and have normally diffuse sound fields.
Intensity Equations in Ray Acoustics. I
Authors: Uginčius Peter
Published: September 2005

A set of differential equations is derived for calculating the intensity loss due to geometrical spreading of planar sound rays in an inhomogeneous medium with a continuous index of refraction varying both in depth and horizontally. Boundary conditions are derived for a reflecting surface and for an interface across which the speed-of-sound gradient may vary discontinuously. Exact analytic solutions are given for a two-layered medium, with either a reflecting surface or an interface, in which the speed of sound is a linear function of depth. The differential equations are also solved numerically for a mathematical model of an ocean with a heat source. Intensity contours are presented for rays in the vicinity of a heat source and a heat sink. The heat sink causes the rays to converge, which results in the formation of a caustic.
Frequency Dependence in Temporal Integration
Authors: Bilger R. C. , Feldman R. M.
Published: September 2005

Temporal integration data were collected using three different methods: Békésy tracking, a forced-choice tracking procedure, and a “YES-NO” procedure. Results of the first two procedures, in which intensity variation was under subject control, indicate that the slope of the function relating threshold to signal duration is the same for all frequencies. This independence of the integration function and frequency is in agreement with previous research. However, when a conventional “YES-NO” procedure was used to construct psychometric functions, the resulting curves for temporal integration varied with frequency; being steepest for low frequencies (250 Hz) and least steep for high frequencies (4 kHz). [This research was supported by grants from the National Institute of Neurological Diseases and Blindness, U. S. Public Health Service.]
Temporal Parameters in Startle Facilitation by Steady Background Signals
Authors: Hoffman Howard S. , Wible Barry L.
Published: September 2005

When an intense acoustic stimulus is presented to the rat in a background of steady random noise, the startle reaction is larger than when the same stimulus is presented against a background of silence. Two experiments examined the temporal parameters of this facilitation effect. The initial experiment sought to determine how long the background signal must be present before facilitation can be detected. The second experiment examined the question of how long facilitation persists following termination of a background signal. Results indicated that 100 msec of exposure to a background signal is adequate for full development of the facilitation effect, and that the effect exhibits a significant decline by no more than 8 msec after the termination of a background signal.
Asymptotic Solution for the Sound Field in Shallow Water with a Negative Velocity Gradient
Authors: Denham R. N.
Published: September 2005

A solution, valid at high frequencies, for the sound field in shallow water having a negative velocity gradient is obtained by normal-mode theory. Using this solution, relatively simple expressions for the decay of intensity over intermediate and long ranges can be obtained if it is assumed that propagation is basically governed by the mode with phase velocity equal to the surface sound velocity. The transmission loss as a function of range follows a three-halves-power law at intermediate ranges and a cylindrical spreading law at long ranges. In both regions, attenuation due to bottom losses is assumed to be present, and it is shown that the value of this attenuation is approximately the same as that derived by a ray-theory model. In addition, the results of this analysis are in accord with other semiempirical predictions for the transmission loss in shallow water.
Arbitrarily Reinforced Dome Plate and Flow Noise. I. Signal Reception
Authors: Kuo Edward Y. T.
Published: September 2005

Two parallel infinite plates are proposed for the dome study. The first plate, simulating the dome plate, is in general, arbitrarily reinforced. The second plate, simulating the hydrophone-array plane, is assumed to have a given spectral impedance. The received pressure at a hydrophone and an array of hydrophones is obtained for an incident plane wave going through the dome plate that is also excited by the turbulent pressure. Noises produced by the dome plate and supports are found to be controllable by (a) radiation, (b) amplitude, (c) frequency, and (d) directivity separately or jointly.
Covariance between Acoustic Signals Traveling Diverging Paths in a Random Medium
Authors: Sederowitz William J. , Favret Andrew G.
Published: September 2005

As a random process, the temperature microstructure in water exhibits both time and spatial correlation characteristics. Thus, acoustic signals propagated along diverging or converging paths should indicate some degree of cross correlation due to the temperature microstructure. This dependence is investigated in a water tank with a controlled temperature microstructure. The angular separation between paths is varied and cross-correlation functions are computed for the various separations. The measurements were made using pulsed signals at 500 kHz. The correlation between the received signals decreases as the angular separation between the paths is increased.
DICANNE, a Realizable Adaptive Process
Authors: Anderson Victor C.
Published: September 2005

DICANNE (Digital Interference Cancelling Adaptive Null Network Equipment) is a real-time digital processor that is designed to reject plane-wave interference from an operator-controlled direction prior to normal beam forming. The description includes computed characteristics of the specific array geometry selected and a functional outline of the digital processing equipment.
Unit Responses of the Cat Cochlear Nucleus to Amplitude-Modulated Stimuli
Authors: Glattke Theodore J.
Published: September 2005

Psychoacoustic studies have indicated that the pitch corresponding to the fundamental frequency of certain complex stimuli may be mediated through the temporal pattern of neural discharges. To evaluate this proposal, two populations of units from the cochlear nucleus were examined for their responses to modulated stimuli: (1) Those units with maximum sensitivity for sinusoidal stimuli of 800 Hz or less were presented with modulated stimuli having a low-frequency fundamental, but with spectrum controlled to reduce the contribution of low-frequency energy; (2) units with maximum sensitivity in higher-frequency regions were studied using the stimulus frequency to which each was most sensitive and modulating it at low rates. The results suggests that units were not sensitive to the periodicity characteristics of a stimulus, per se, but that they also require certain spectral information. Once a unit is driven to respond , however, it is likely to reflect the periodicity of the stimulus in its discharge patterns.
Amplitude Discrimination in Noise, Pedestal Experiments, and Additivity of Masking
Authors: Henning G. Bruce
Published: September 2005

The masking effect of a broad-band noise, a sinusoidal tone, or both may be represented in a simple three-dimensional space. The space shows performance as function of (1) the level of the sinusoidal components relative to the noise, and (2) the relative energies in the signal plus sinusoidal masker waveform and the waveform of the sinusoidal masker alone. Results that appear complex in other representations appear straightforward in this space. For example, over wide ranges, neither frequency and duration of the signal nor the relative interaural phase of the signal and masking stimuli affects the shape of the space, but produces, at most, only a simple translation. Several theoretical descriptions of the space are discussed.
Thermal and Electronic Attenuations and Dislocation Drag in the Hexagonal Crystal Cadmium
Authors: Mason Warren P. , Rosenberg Arthur
Published: September 2005

Thermal attenuations for dielectric crystals due to the Akheiser effect show characteristic patterns connected with crystal structure. For cubic crystals, the nonlinearity constants D—which determine the coupling of acoustic waves with the thermal phonons—are all larger for the longitudinal waves than they are for the shear waves by ratios that vary from 5 to 17. On the other hand, for trigonal and hexagonal crystals, the constants are in the same order. It is the purpose of this paper to investigate whether these conclusions hold for metal crystals. For these crystals, there are three sources of square-law attenuation for longitudinal waves and two for shear waves. These are the thermoelastic effect, the phonon viscosity (Akheiser effect), and the electron-damping effect. Previous measurements for the cubic crystals lead, aluminum, and copper, made over a temperature range, are analyzed for these three components, and it is shown that the phonon viscosity D values vary from 5.3 to 17.5 for the ratio of longitudinal to shear values in agreement with the results for dielectric crystals. New measurements are presented for the hexagonal single crystal cadmium. It is shown that all dislocation motions, generated by the small strains used, lie in the direction of easy glide, i.e., in a plane perpendicular to the c axis. The longitudinal wave along the c axis and the three waves perpendicular to c all have only a square law attenuation. When the thermoelastic effect and the electronic damping effect are subtracted out, the nonlinearity constants have the same order of magnitude for both longitudinal and shear waves. Dislocation damping appears in the shear wave in the c direction. The ratio of the number of dislocations to the damping constant is evaluated and is shown to be smaller than that for other pure crystals. This is consistent with phonon damping of dislocations on account of the large nonlinearity constant D found for shear motion in the glide plane. When an attempt was made to measure this damping over a temperature range, it was found that a sudden increase in the attenuation occurs for shear waves controlled by the c44 elastic constant.
Responses from Single Auditory Units in the Eighth Nerve of the Leopard Frog
Authors: Liff Harold
Published: September 2005

Auditory units in the eighth nerve of the leopard frog (Rana pipiens) are frequency selective with best frequencies from less than 100 Hz to near 2000 Hz. There are two distinct types of units, simple and complex. Simple units are most sensitive to high-frequency tones, are usually spontaneous, and cannot be inhibited by sound. Complex units usually have best frequencies below 700 Hz and each can be inhibited by tones with frequencies above its best frequency. The primary auditory units of the leopard frog are similar to those found in the bullfrog and the green frog. A preliminary study of the spectral characteristics of R. pipiens mating calls indicates that both types of units would be excited by these sounds. This suggests that mating-call detection in the leopard frog may depend upon the excitation of simple and complex units, as it does in the bullfrog.
Comments on “Historical Background of the Haas and or Precedence Effect” [M. B. Gardner, J. Acoust. Soc. Amer. 43, 1243–1248 (1968)]
Authors: Parkin P. H.
Published: September 2005

The justification for the term “Haas effect” is discussed.
Detection of Cavities Produced in a Liquid by Ionizing Particles
Authors: Marietti P. , Sette D. , Wanderlingh F.
Published: September 2005

A new technique for the detection of cavitation nuclei in liquids is developed. Microbubbles created by high energy ionizing particles give rise to an additional absorption of sound, at frequencies determined by their size. From the experimental measurement of the acoustic absorption coefficient as a function of the frequency, the presence of bubbles of various sizes can therefore be detected. In the present work microbubbles created in water by fission fragments of the 238U are detected. We use a reverberation method allowing a continuous variation of frequency in the range 100–900 kc/sec. The signal was treated by means of a sampling technique that allows one to get a fast response with an accuracy sufficient for our purposes. The size distribution of microbubbles produced in the 238U solution appears closely related to the well-known energy distribution of fission fragments.
Theoretical Investigation of the Integrated Optical Effect Produced by Sound Fields Radiated from Plane Piston Transducers
Authors: Ingenito Frank , Cook Bill D.
Published: September 2005

An expression, valid in the Raman-Nath region, is derived for the integrated optical effect experienced by a light beam traversing the sound field of a plane piston transducer of arbitrary shape. Specific results for circular and rectangular transducers are discussed. Of particular interest is the optical effect produced by a square transducer aligned so that the light beam propagates in a direction parallel to one of the diagonals. In this case, the integrated optical effect is nearly constant over a fairly large region in space, suggesting the possibility of using this configuration to make absorption measurements.
Effect of Large-Amplitude Static and Dynamic Stress on the Mechanical Loss of Lead Zirconate Titanate Transducer Ceramic
Authors: Whymark Roy R. , Triebes Kenneth J.
Published: September 2005

The effect of static and dynamic stress on the mechanical loss of a piezoelectric ceramic has been measured. Static stress was applied pneumatically along the axis of a radially polarized tube of lead zirconate titanate measuring 2.54 cm long by 0.317 cm wall thickness. It was found that immediately after applying a static compressive stress of 3000 psi, the mechanical loss, proportional to the reciprocal mechanical quality factor Qm−1 increased from 1.27×10−3 to 4.54×10−3. The mechanical loss of the ceramic was determined by measuring the Q factor of the ceramic and its support, and correcting for the support losses. A similar tube was statically biased with a stress bolt by incorporating the tube as the active element in a small model transducer. The transducer was then coupled to a high-power ultrasonic driver by means of which large dynamic stresses were generated in the ceramic. A dynamic stress of 3000-psi peak was superposed on a static biasing stress estimated at 5000 to 10 000 psi. The bias alone increased the Qm−1 factor of the tube from 4.00×10−3 to 2.45×10−2, and the superposed dynamic stress further increased the Qm−1 factor to 6.30×10−2. Upon removing the dynamic stress, the Qm−1 factor gradually reduced to 1.67×10−2. Surface temperature rise did not exceed 5°C.
Coupling through Small Apertures, with an Application to Helmholtz' Resonator
Authors: Van Bladel J.
Published: September 2005

The problem of the cavity with a small aperture is reduced to the solution of an integral equation, which is solved both for low frequencies and frequencies around a resonant value. Use of a reciprocity principle leads directly to an equivalent circuit for the cavity.
Shear-Flexure-Twist Vibrations in Rectangular AT-Cut Quartz Plates with Partial Electrodes
Authors: Lee P. C. Y. , Spencer W. J.
Published: September 2005

The equations of motion including thickness-twist overtones of thickness shear and flexural vibrations have recently been given for AT-cut quartz plates [R. D. Mindlin and W. J. Spencer, J. Acoust. Soc. Amer. 42, 1268–1277 (1967)]. These equations are here applied to a rectangular quartz plate with a metallic electrode strip. The equations are solved for the case with all four edges free and the resonant frequencies and displacements are computed as a function of electrode mass and plate geometry. The pertinent resonances in the single-crystal plates have been identified by x-ray diffraction topography and the measured frequencies are compared with the computed values. The importance of the electrode in suppression of particular vibrations is briefly discussed.
Flextensional Underwater Acoustics Transducer
Authors: Royster L. H.
Published: September 2005

The basic principles of the flextensional underwater acoustic transducer are investigated by developing a mathematical model representation for this type of transducer system, and then establishing the effects that the various geometrical parameters have on the systems performance. The acoustic radiation problem is solved by numerically evaluating the Helmholtz integral for the farfield and nearfield pressure distributions. The mechanical shell vibration problem is simplified by replacing the continuous shell with an analogous framework consisting of a series of bars and joints and having a finite number of degrees of freedom. Finally, the coupled stack wave equation is solved in terms of an arbitrary terminal impedance that simulates the combined impedance of the shell and acoustic radiation impedances. Values of transducer impedance, farfield radiation pressures, and effective electromechanical coupling coefficients are calculated and compared with published experimental values for the University of Miami flextensional underwater acoustic transducer.
Temporal Integration and Periodicity Pitch
Authors: Campbell Richard A. , Counter S. Allen
Published: September 2005

Auditory temporal integration and periodicity pitch perception seem to be based on mutually exclusive neural processes in the auditory system. Explanations for these two phenomena involve neural temporal persistence, on the one hand, and temporal resolution on the other. Data are herein presented indicating a drastic reduction of temporal integration of energy at threshold for frequencies below 250 Hz with durations of from 4 to 400 msec with virtually no temporal integration observed at 125 Hz. These data and other considerations support the notion that there is a lower frequency limit of 100–200 Hz for auditory temporal integration of energy. This lower frequency limit corresponds to the upper frequency limit for periodicity pitch perception, the maximum rate at which individual auditory-nerve units have been observed to fire and the maximum frequency to which the cochlear partition responds essentially in phase.
Perceptual Masking in Multiple Sound Backgrounds
Authors: Carhart Raymond , Tillman Tom W. , Greetis Elizabeth S.
Published: September 2005

Shifts in masked spondee thresholds during several conditions of listening (monaural, homophasic, antiphasic, and with interaural time disparity) in the presence of one to four competing maskers were measured. The maskers used were white noise, white noise modulated four times per second by 10 dB with a 50% duty cycle, the same noise with 75% duty cycle, connected speech by one male talker, and connected speech by a second male talker. Results from three experiments that employed various permutations of the aforementioned conditions are reported. The findings, after equating conditions to equivalent masker levels, were four. First, the modulated noise with 50% duty cycle produced about 3.5 dB less masking than that produced by unmodulated white noise. Second, the modulated noise with 75% duty cycle allowed only about 1 dB less shift than did the unmodulated noise. Third, mixing one speech train with noise (either modulated or unmodulated) induced about 3.2 dB excess masking. This excess is here termed perceptual masking. Fourth, perceptual masking rose to 6.6 dB when two speech trains were included in the masker complex, irrespective of whether or not noise was also part of the complex. The findings support the hypothesis that successive stages of perceptual masking arise as the task of signal sorting becomes more exacting for the listener. Related studies are discussed in this connection.
Auditory Temporal Masking and the Perception of Order
Authors: Homick J. L. , Elfner L. F. , Bothe G. G.
Published: September 2005

An investigation of the effects of frequency, intensity, and time on the perception of temporal order and the amount of temporal masking produced under conditions of a short burst (12 msec) of tone separated temporally from a narrow-band noise indicates a similarity of function underlying the two phenomena. Temporal masking is greater and the perception of temporal order is more difficult when the signal is centered in the band of noise. Temporal masking is greater and the perception of temporal order is more difficult for a weak signal than for a more intense signal. The observed temporal masking can be interpreted in terms of a cochlear model. The relationship between temporal masking and the perception of temporal order is discussed in terms of a hierarchy of level of perception brought about by temporal cues.
Perception of (Hindi) Consonants in Clipped Speech
Authors: Gupta J. P. , Agrawal S. S. , Ahmed Rais
Published: September 2005

Perceptual confusions of 29 initial and 31 final consonants, embedded in nonsense CVC syllables, have been studied in infinite peak clipping. It is found that the consonants (t∫, t∫h, dȝ, dȝh, k, kh, gh, s, ∫, j, r, l, w) are better recognized than the consonants (p, ph, b, bh, m, t, th, d, dh, n, .t, .th, .d, .dh, .r, .rh, ň, g, h). The effect of clipping on the intelligibility degradation of the features has been observed in both positions of consonants and the average effect is graded as follows: (1) place, (2) nasality, (3) flapped liquids, (4) liquids, (5) continuants, (6) voicing, (7) friction, (8) aspiration, (9) affriction. Comparison of the rank orders of features of normal speech with clipped speech indicates that the two types of speech are alike for the relative importance of the features. Moreover, a study of correlation of rank orders for initial and final consonants supports the view that the initial and the final consonants are not similar in respect to perceptual cues.
An Extension of Some Observations of Leshowitz and Raab
Authors: Henning G. Bruce , Psotka Joseph
Published: September 2005

Leshowitz and Raab (1967) suggest that detection performance remains constant when the increment energy is fixed in spite of wide variation in both signal level and duration. Extension of the observation used to support this suggestion indicate that changes in performance result from changing signal duration even when the increment energy remains constant.
Suprathreshold Auditory Adaptation
Authors: Palva T. , Kärjä J.
Published: September 2005

Perstimulatory suprathreshold adaptation was measured in 38 normal adult persons between 250 and 6000 Hz at 20, 40, 60, and 80 dB SL. In the experimental ear, the continuous stimulus had a constant intensity. In the control ear, the adjustable balancing stimulus had a duration of 200 msec with a silent interval of similar length. Adaptation increased at all frequencies as a function of SL up to 60 dB, but testing at 80 dB brought no further increase. At low tones, adaptation was smaller than at high frequencies. There were large individual differences; 5% showed no adaptation at all, 45% a very rapid growth, and 50% a slower adaptation reaching a maximum in 212–3 min. Average adaptation was 30 dB at the high frequencies. In children, the same test generally revealed no adaptation at all; in old age, adaptation was comparable to the normal adult group.
Stimulus-Response Relation for Auditory-Noise Fibers: Two-Tone Stimuli
Authors: Sachs Murray B.
Published: September 2005

Spike discharges from single fibers in the auditory nerve of anesthetized cats were recorded with micro-electrodes. Rates of discharge were measured as functions of the frequencies and levels of either single tone bursts or of the sum of two simultaneous tone bursts. From these data, a mathematical expression relating rate of discharge to parameters of a two-tone stimulus is derived. The rate of response is written as the sum of a “spontaneous” part and a driven part. The driven part of the response to two tones is a weighted sum of the driven parts of the responses to the individual tones presented alone. The weighting factors to a first approximation depend only on the ratio of the levels of the two tones and on their frequencies. The relationship of this stimulus response formulation to existing data and to auditory system models is discussed.
On Sound-Transmission Anomalies in the Atmosphere
Authors: Ingard Uno
Published: September 2005

Three sound-transmission anomalies in the atmosphere are discussed, and explanations are suggested.
Comments on “Numerical Evaluation of the Radiation Impedance for a Piston in a Nonrigid Baffle” [D. Feit and M. E. Duncan, J. Acoust. Soc. Amer. 43, 885–886(L) (1968)]
Authors: Mangulis Visvaldis
Published: September 2005

Various choices for the boundary condition on a piston radiating from a nonrigid battle are discussed.
Comments Concerning the Determination of Absolute Sound Speeds in Distilled and Seawater and Pacific Sofar Speeds
Authors: Lovett J. R.
Published: September 2005

The preponderance of recent determinations of distilled-water sound speed indicates that the Wilson (for the range 0°–30°C) and Greenspan-Tschiegg sound-speed equations are too high by 65 and 40 cm/sec, respectively. Similarly, the Wilson seawater sound-speed equation gives Pacific temperate latitude Sofar speeds 23 m/sec higher than values based on explosion travel times. Adjusted distilled and seawater equations are proposed in order to achieve a common standard for all measurements at sea.
Rapid Sampling of Acoustic Holograms by Laser-Scanning Techniques
Authors: Korpel A. , Desmares P.
Published: September 2005

The paper discusses a technique in which a laser flying spot scanner is used to record an acoustic hologram by reading out the periodic deformations of a solid surface caused by an incident sound field. The technique is compared with the Sokolov tube method and shown to have comparable sensitivity, while not being restricted to low frequencies and small areas. A description is given of experiments using sound frequencies of 2 and 9 MHz, and photographs are presented showing holograms and reconstructions obtained with this technique.
Holographic Imaging with Ultrasound
Authors: Thurstone Fredrick L.
Published: September 2005

The use of holographic imaging techniques with acoustical investigating fields offers the possibility of presenting three-dimensional visual images of optically opaque structures. The fundamental limitations on such an imaging technique are presented, and the methods that have been used together with the basic requirements for this imaging process are discussed. Several techniques are presented for the reduction of the image distortion associated with the wavelength ratio of acoustical energy to electromagnetic energy in the visible spectrum including a nonlinear holographic technique that produces equal lateral and longitudinal image magnification.
Impact on an Elastic Quarter Space
Authors: Wright T. W.
Published: September 2005

Impact loads are applied on one semi-infinite surface of an elastic quarter space while the other semi-infinite surface is maintained stress free. Boundary conditions on the loaded surface are of the mixedtype (one component of traction and one of displacement). A plane wave normal to the free surface is accompanied by diffracted waves that radiate from the intersection of the bounding surfaces. In the case of normal loads, the problem is relevant for the short-time response of colliding bodies. In the case of shear loads, the solution helps illuminate the problem of sharp fronted waves that exceed a critical angle at a boundary.
Hydroacoustic Signals from the CHASE V Explosion
Authors: Kibblewhite A. C. , Denham R. N.
Published: September 2005

Hydroacoustic signals from the 1-kton CHASE V explosion detonated off Cape Mendocino, California, were recorded on hydrophones off the east coast of the North Island of New Zealand. Reverberation signals continued for about one hour after the main arrival. While most parts of this signal could be attributed in a general way to extensive underwater features, in some cases there were discrete arrivals that could be positively identified with specific topographical features in the south east of the Pacific Ocean. The travel-time results indicate that essentially rectilinear transmission was involved even though the detonation and receiving points are separated by 10 000 km.
Effect of Edge Vibrations on the Propagation of a Strain Transient
Authors: McCoy J. J.
Published: September 2005

The Mindlin-McNiven equations are used to study the response of a linearly elastic semi-infinite rod to a time-varying pressure suddenly applied to its otherwise free end. The solution is presented as the sum of two parts. The first part is the response that is obtained if the end to which the pressure is applied is restrained from any radial motion. The second part represents the difference in response that arises due to a relaxation of this radial constraint. A numerical investigation of the latter term in the Fourier transform domain discloses two poles, symmetrically placed with respect to zero frequency, which are close to but immediately below the real frequency axis. These poles are the source of the edge-resonance phenomenon for steady vibrations that has been reported by McNiven and are also the source of the long tail noted in the experiments of Oliver. The form of the correction term in the real time domain is obtained by the method of steepest descent for times in the vicinity of that at which a saddle point comes closest to colliding with each of these poles in the complex frequency plane.
Pulsed Circumferential Waves on Aluminum Cylinders in Water
Authors: Neubauer Werner G.
Published: September 2005

Three types of waves that contribute to the total acoustic diffracted field of an aluminum cylinder in water are isolated by generating each wave to the exclusion of the other two. The “Franz-type” or “creeping” wave is generated separately on the outside of aluminum cylinders with ka values ranging from 54 to 1008. The circumferential-wave speed is found to be 1% less than that of the free waterborne wave, in agreement with the theory for a rigid cylinder. The attenuation of these waves on aluminum cylinders is significantly less than that predicted by the theory for the rigid cylinder. Another circumferential wave, with approximately a 30° incidence and emergence angle, is found to propagate on the inside of the curved boundary. This wave has an attenuation ranging between 0.10 and 0.18 Np/rad and has a speed of 2.5 times that of the free waterborne wave. This is classified as a “Rayleigh type” wave. A third wave is observed that is similar to the wave generated at 30° incidence but has a 15° incidence and emergence angle. The attenuation is between 0.08 and 0.14 Np/rad and has a speed of 6.5 times that of the free waterborne wave. Experimental measurements of differential-scattering cross section are compared with those calculated by means of the creeping-wave formulation.
Monaural Loudness-Intensity Relationships for a 1000-Hz Tone
Authors: Rowley Rodney R. , Studebaker Gerald A.
Published: September 2005

This investigation was designed to obtain the monaural loudness function for a 1000-Hz tone. Ten trained observers with normal hearing were utilized. The method used was the numerical magnitude balance procedure. This investigation indicates that the results obtained by the numerical magnitude balance procedure are repeatable if the observers do not have previous knowledge of the decibel scale, and if they are properly trained. This is indicated by the good agreement of the results of this study with the findings of previous studies. The results of this study showed a loudness exponent of 0.54 based on data averaged by geometric means and 0.51 based on data averaged by medians.
Experimental Detection of Evanescent Ultrasonic Waves by Bragg Diffraction of Light
Authors: Wade Glen , Powers John P. , deSouza Alwyn A.
Published: September 2005

The presence of evanescent ultrasonic waves diffracted from an acoustic grating has been detected using Bragg diffraction of laser light. The diffraction of light by these evanescent waves (whose concept stems originally from theoretical arguments) confirms their physical existence. The grating used was designed to diffract the sound into two kinds of wave components: (1) a single propagating wave component moving directly away from the grating; and (2) a pair of oppositely directed evanescent-wave components traveling along the back surface of the grating and forming a standing evanescent wave with exponential decay perpendicular to the grating. Such evanescent waves have shorter wavelengths than propagating waves and hence are inherently capable of better resolution if used for imaging. With the proper orientation of the laser beam with respect to the grating, theory predicts that the above wave components will produce diffracted spots of light symmetrically placed about a central axis. The spots due to the evanescent-wave components are found on an axis perpendicular to that of the spots due to the propagating-wave component, and the evanescent-wave spots are further away from the center. Detection and measurement of the positions and the relative intensities of the spots gives information about the wavelengths of the components and about the rate of exponential decay of the evanescent wave.
Echo Phase-Comparison Technique and Measurement of Sound Velocity in Water
Authors: Williamson R. C.
Published: September 2005

A technique is described in which the ultrasonic time delay between successive echoes in an echo train is determined by phase comparison of the echoes with a coherent continuous signal. Corrections for phase shift of an echo upon reflection from the face of a transducer and for diffraction effects are discussed. The velocity of sound at 1 MHz in distilled water from 23° to 75°C has been measured with this technique. Measurements of time delay are accurate to 20 ppm while the over-all accuracy is 127 ppm or ±0.20 m/sec. Excellent agreement with values in the literature is found.
Reflection of Plane Waves from the Flat Boundary of a Micropolar Elastic Half-Space
Authors: Parfitt V. R. , Eringen A. C.
Published: September 2005

This paper is concerned with the investigation of the effect of microstructure in the solution of several problems of wave propagation. The propagation of plane waves in a micropolar elastic half-space and their reflections from a stress free flat surface are studied. It has been found that in a micropolar elastic solid, four waves can exist traveling at four distinct speeds, two of which disappear below a critical frequency dependent upon the character of the medium. Reflection laws and amplitude ratios are presented for three specific problems.
Comments on “Bending Frequencies of Compressed Beams” [A. E. Galef, J. Acoust. Soc. Amer. 44, 643 (L) (1968)]
Authors: Amba-Rao C. L.
Published: September 2005

An abstract from a classical reference pertaining to the correspondence between the natural frequency of compressed bars and buckling loads is quoted.
Technique for Enhancing Signals for Auditory Detection
Authors: Lummis R. C. , Schroeder M. R.
Published: September 2005

If a narrow-band signal imbedded in noise is recorded and reproduced at higher speed, then heterodyned to restore the signal to its original frequency, the signal-to-noise ratio measured with a bandpass filter centered on the signal frequency will be increased. This procedure is useful when the human auditory system is to serve as the analyzer and detector, because it permits the signal bandwidth to be matched to the fixed analyzing bandwidth of the ear.
Dislocation Contribution to Ultrasonic Attenuation in Zinc Crystals as Function of Orientation, Irradiation, Plastic Deformation, and Recovery
Authors: Lenz D. , Lücke K. , Ostermann A. , Sibley W. A.
Published: September 2005

The ultrasonic attenuation in zinc single crystals has been measured between 5 and 105 MHz for all pure modes possible in this metal. By comparing the results with the orientation factors of the Granato-Lücke theory of dislocation resonance damping, the contribution of dislocations on {112̄2} planes to the attenuation has been quantitatively determined. The participation of nonbasal dislocations has also been proved by measurements of dislocation pinning due to γ irradiation and recovery thereafter. The recovery of the attenuation has been measured between 77° and 350°K. Recovery steps have been found at about 105° and 160°K. Measurements of the recovery after plastic deformation in the temperature range from 230° to 300°K yield an activation energy of 0.56 eV.
Electromagnetic Generation of Ultrasonic Waves in Metals
Authors: Meredith D. J. , Watts-Tobin R. J. , Dobbs E. Roland
Published: September 2005

The electromagnetic generation of pure shear and quasicompressional sound waves in metals for propagation, respectively, parallel to and perpendicular to a static magnetic field is investigated for a wide temperature range. Using a semiclassical model of a free electron gas moving against a positive ion background carrying the sound wave, the magnitude of the ionic displacements in the helicon geometry is calculated, together with the propagation constants. In the long-wavelength limit, the excited mode that propagates differs only slightly from a normal acoustic shear mode. Satisfactory agreement is obtained when these calculations are compared with our experimental results at room temperature, 77° and 4.2°K in static magnetic fields of up to 100 kG.
New Formulation of Acoustic Scattering
Authors: Waterman P. C.
Published: September 2005

Upon introducing the outgoing spherical (or circular cylinder) partial waves {ψn} as a basis, the equation QT = − Re (Q) is obtained for the transition matrix T describing scattering for general incidence on a smooth object of arbitrary shape. Elements of Q involve integrals over the object surface, e.g. Qmn = ±(i2)δmn+(k8π)∫dσ⋅∇[Re(ψm)ψn]. where the −, + apply for Dirichlet and Neumann conditions, respectively. For quadric (separable) surfaces, Q is symmetric. Symmetry and unitarity lead to a secular equation defining eigenfunctions for general bodies. Some apparently new closed-form results are obtained in the low frequency limit, and the transition matrix is computed numerically for the infinite strip.
Consonance Theory Part I: Consonance of Dyads
Authors: Kameoka Akio , Kuriyagawa Mamoru
Published: September 2005

Extensive psychological experiments were carried out in this Part I on the consonance sensation of various dyad tones consisting of two components. As the frequencies of two components f1 and f2 (with an equal SPL) separate, the consonance gradually decreases down to the most dissonant point, whereafter it monotonically increases and mostly recovers at an octave separation. This consonance characteristic turned out to show a simple V curve if consonance is plotted against the frequency percent deviation in a logarithmic scale, and it suggests a dynamic and a static factor in consonance perception. The most dissonant frequency deviation is approximately 10% at f1=440 Hz, and it increased with sound pressure and frequency, but it was not simply proportional to the critical bandwidth. For dyads whose two components have different sound-pressure levels (SPLs) L1 and L2, the consonance differs with spectrum forms, even when the level difference is the same. A dyad with a spectrum form (P1>P2, f1<f2) was more dissonant than that with its opposite spectrum form (P1 < P2). This asymmetrical property suggests a common origin in consonance perception with that observed in pure-tune masking or neural response pattern. The results obtained in this Part I provide fundamental data to theoretical consonance calculation to be described in Part II for static complex tones consisting of more than three components.