bluuebunny/crossref_metadata_2025_split huggingface dataset:
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Authors: Dooling Robert J. , Saunders James C. 
Published: October 2005

Three parakeets were trained by a method of avoidance conditioning to respond to intensity differences in successsively occurring tone bursts. Intensity difference limens were obtained at six sensation levels of a 2.86 kHz tone. The relative intensity difference limens (ΔI) for the parakeet were larger than similarly reported measures for man and other mammals at all sensation levels tested. Calculations of the Weber fractions at each sensation level tested showed that Weber’s law holds for the parakeet at sensation levels above 50 dB.
Subject Classification: 80.50; 65.75, 65.50.
Comments on ’’Propagation of normal mode in the parabolic approximation’’ [Suzanne T. McDaniel, J. Acoust. Soc. Am. 57, 307–311 (1975)]
Authors: Williams A. O. 
Published: October 2005

Three comments are offered to complement McDaniel’s recent analysis of errors due to the parabolic approximation. First, it is shown that both the parabolic method and the somewhat similar WKB method yield good approximations for the amplitude of the acoustic field, in underwater sound propagation, but the WKB phase result is much superior. Second, another test of phase errors is proposed, that of zone or channel convergence; it turns out the parabolic method should handle such cases quite adequately. Third, the demonstrated greater success of the parabolic method for the lower normal modes of a many-mode set is explained as stemming from the algorithm used in numerical solutions.
Subject Classifications: 30.20; 20.40, 20.15.
Historical review of horns used for audience-type sound reproduction
Authors: Hilliard John K. 
Published: October 2005

This paper reviews the history of horns used in loudspeaker systems for audience-type sound reproduction. It reviews the early pioneering work started around 1910 which used telephone-type transmitters before vacuum tube amplifiers were available. With the availability of amplifiers more powerful driver type loudspeakers were developed to operate with exponential straight and folded horns. Sound motion pictures created a demand for higher quality, and higher-powered loudspeaker systems for both voice and music. The many stages of development of two-way loudspeaker systems are reviewed. The limitations of each stage of development before proceeding to the next improvement is discussed. Photographs of many early horns are included as well as the more recent types.
Subject Classification: [43]10.60; [43]85.60.
Wake-related sound generation from isolated airfoils
Authors: Clark Larry T. , Chalupnik James D. , Hodder Brent 
Published: October 2005

A model for the prediction of wake-related sound generation by a single airfoil is presented which assumes that the net force fluctuation on an airfoil can be expressed in terms of the net momentum fluctuation in the near wake of the airfoil. The model predicts a forcing function for sound generation which is related to the spectra of the two-point velocity correlations in the turbulent region near the airfoil trailing edge. Cross spectra were obtained from correlations of the longitudinal and transverse components of turbulence in the wake of a 36-in. chord NACA series 63-009 airfoil in the 7×10 ft tunnel at the NASA Ames Research Center using x-probe hot-wire sensors. Additional data were obtained from a 10-in. chord airfoil in a free-jet facility at the University of Washington. Based on results from these tests, a scaling model was developed using the turbulent boundary-layer thickness as the primary length measure. The model was used to predict the sound radiated from a 2-in. chord airfoil for which acoustical data is available with good agreement both in level and spectral shape. The single airfoil result is extended to a rotor geometry and comparisons studied for various aerodynamic parameters.
Subject Classification:[43]28.65; [43]50.55.
Acoustic reflection from a structured sea bottom
Authors: Williams A. O. 
Published: October 2005

Acoustic reflection coefficients for reflection from ocean bottoms are sometimes calculated for postulated models of the bottom structure. A published example, using a model based on geophysical data, is examined with attention to possible simplification and to the physical links between model and computer output. It is shown that calculated results at small grazing angles have a physical cause and can be well approximated by a simpler model. It appears, however, that at larger angles the results are not physically reasonable. The cause is that a commonly used ’’pseudolinear’’ gradient of sound speed is unphysical in a half space, because at a certain finite depth the sound speed becomes infinite, and imaginary at greater depths. A physically reasonable profile of sound speed is proposed as a substitute and expressions for the reflection coefficient are derived in the approximation of vanishing absorption. At that stage, the expressions are considerably simpler than those of the published example. An extension incorporating absorption is planned.
Subject Classification: [43]30.20, [43]30.30.
Sonar for generalized target description and its similarity to animal echolocation systems
Authors: Altes Richard A. 
Published: October 2005

Range-distributed targets are often characterized as arrays of point scatterers. This conceptualization corresponds to a target impulse response that is a sequence of impulses. A physically meaningful generalization of this description is obtained by modeling an impulse response in terms of pulse doublets, impulses, step functions, ramp functions, etc., i.e., as a superposition of delayed impulses and differentiated or integrated impulses. A sonar system for generalized target characterization is derived in this paper. Signals and receivers are specified for (1) optimum estimation of reflector parameters and (2) detection of a known target in clutter. The derived signals correspond closely with some of the waveforms that are used by dolphins and bats for echolocation. The corresponding echo analyzers are similar to psychoacoustic models of the mammalian hearing system.
Subject Classification: [43]60.20, [43]60.50; [43]30.82; [43]80.50.
Effective quiet and moderate TTS: Implications for noise exposure standards
Authors: Ward W. Dixon , Cushing E. Marion , Burns Edward M. 
Published: October 2005

’’Effective quiet,’’ the highest SPL of a noise that will neither produce a significant temporary threshold shift (TTS) nor retard recovery from a TTS produced by a prior exposure to a higher level, is shown to be about 76 dB for octave bands of noise centered at 250 and 500 Hz, and around 68 dB for those centered at 1000, 2000, or 4000 Hz. On the other hand, a mean TTS2 (TTS 2 min after exposure) of no greater than 10 dB at all frequencies from 500 to 5600 Hz is produced by a broad-band noise whose octave-band spectrum falls off at −5 dB per octave (’’magenta’’ noise) and which has an A-weighted level of 90 dBA. When the group mean TTS2 is 10 dB, less than 10% of normal ears will show a TTS2 of 20 dB. Therefore if a 20-dB TTS2 is tolerable day after day with no adverse effects, the present industrial noise exposure limit of 8 h at 90 dBA would adequately protect more than 90% of exposed workers in noises with similarly falling spectra. Correction factors for unusual spectra should, however, be developed.
Subject Classification: [43]65.66, [43]65.64; [43]50.70.
Middle ear pressure: Effects on the auditory periphery
Authors: McPherson D. L. , Miller J. M. , Axelsson A. 
Published: October 2005

The effects of direct variation in static middle ear pressure were studied in the acute guinea pig. Pressure differences of from −500 to +500 mm of H2O were examined. Pure tones were delivered to the test ear in a closed system and the sound pressure levels monitored with a condenser microphone and probe tube situated 2 mm from the tympanic membrane. The cochlear microphonic was recorded from a round window electrode. Both the relative impedance change and cochlear microphonic were noted at various middle ear pressure levels. The animals were perfused with Prussian blue and cochleas stained with osmic acid and prepared for histopathological study. It was found that negative pressure causes greater changes on impedance and transmission than positive pressure. Increase in positive pressure was found to cause a monotonic increase in input impedance and decrease in transmission. For negative pressures, the effect was nonmonotonic. Observed changes in transmission with both positive and negative pressures could be accounted for only in part by changes in input impedance of the middle ear. Morphological findings showed some discrete dilation of the vessels on the malleus and the tympanic membrane.
Subject Classification: [43]65.24, [43]65.40.
Experiments on ultrasonic cavitation in liquid helium in the presence of second sound
Authors: Dhingra H. C. , Finch R. D. 
Published: October 2005

Cavitation in liquid helium was induced using an ultrasonic cylindrical transducer resonant at approximately 57 kHz. Interaction of the sound field with superfluid helium during cavitation runs was studied using a low-power second-sound signal. This signal was observed to decay when a voltage whose amplitude increased linearly with time was applied to the ultrasonic transducer. This is interpreted as being due to the growth of turbulence in the liquid. It is contended that for the sound field to induce cavitation, the liquid has to be in a state of turbulence. It is possible that there is a threshold for additional attenuation of the second-sound signal near the onset of cavitation. Some cavitation runs were also made in the presence of a high-power second-sound current. Under these circumstances turbulence was generated, either by the second-sound field or by the associated steady heat current. This turbulence lowered the cavitation threshold.
Subject Classification:[43]25.60; [43]35.32, [43]35.47.
Monaural loudness adaptation at low sensation levels in normal and impaired ears
Authors: Margolis Robert H. , Wiley Terry L. 
Published: October 2005

Monaural loudness adaptation was measured in subjects with normal hearing and in subjects with noise-induced sensori-neural hearing loss using a dichotic delayed balance procedure. Adapting stimuli were presented at two sensation levels (15 and 25 dB SL), two frequencies (500 and 4000 Hz), three durations (1, 30, and 60 sec) and two inter-stimulus intervals (10 and 400 msec) and the loudness of the terminal portion of the adapting stimuli was measured with a method of constant stimuli. No loudness adaptation occurred under any conditions for the normal subjects. Hearing-impaired subjects demonstrated small amounts of loudness adaptation, but the occurrence of adaptation did not always coincide with the frequency region of the hearing loss. There was no effect of interstimulus interval for either subject group.
Subject Classification: [43]65.50, [43]65.64, [43]65.66.
Loudness adaptation in listeners with noise-induced hearing loss
Authors: Wiley Terry L. , Lilly David J. , Small Arnold M. 
Published: October 2005

Loudness-adaptation measurements were made using a monaural procedure at 10-, 20-, and 40-dB SL for 500 and 4000 Hz in six subjects with noise-induced hearing loss. The results indicated loudness adaptation only for 10-dB SL at 4000 Hz (where hearing loss was present) and for only three of the subjects. The findings support similar data obtained using dichotic (heterophonic) loudness-balance and threshold tone-decay techniques.
Subject Classification: [43]65.50, [43]65.64; [43]50.70.
Effects of learning English as a second language on the acquisition of a new phonemic contrast
Authors: Streeter L. A. , Landauer T. K. 
Published: October 2005

Very sharp discrimination functions for the timing of voice onset relative to stop release characterize perceptual boundaries between certain pairs of stop consonants for adult speakers of many languages. To explore how these discriminations depend on experience, we studied their development among Kikuyu children, whose native language contains no stops in which voicing is substantially delayed relative to stop release (e.g., /p/). Kikuyu distinguishes stops in which voice onset substantially precedes release (prevoiced) from those in which voice onset is nearly simultaneous with release (voiced) for apical and velar places of articulation. However, the language has only a single prevoiced labial stop. Prior to exposure to English, children discriminated prevoiced from voiced labials and voiced from voiceless labials, although these distinctions are not phonemic in Kijuyu. Moreover, the voiced/voiceless discrimination for labials ([ba] versus [pa]) improved markedly with schooling in English, rapidly surpassing the prevoiced/voiced distinction. Apparently, certain voice onset time differences are naturally discriminable, but it is also apparent that the very fine voiced/voiceless discrimination among adults for whom it is phonemic is largely attributable to experience.
Subject Classification: [43]70.30, [43]70.70.
Intensity–range relations for shallow-water sound propagation
Authors: Murphy Edward , Olesen Ole V. 
Published: October 2005

Convincing experimental evidence is presented to show that various ’’decay laws’’ for the decrease of sound intensity with increasing range can give high-quality representation for shallow water data. However, while a sequence of decay laws may fit data well and are simple, the transition ranges for changeover from one law to another can show a complicated dependence on frequency and environmental parameters. Transition ranges are probably no easier to predict or model than is the transmission loss itself.
Subject Classification: [43]30.20, [43]30.25.
Cross correlation of short-time spectral histories
Authors: Flaska M. D. 
Published: October 2005

Two-dimensional cross correlation of short-time power spectral histories (energy distribution functions) is a hybrid signal-processing technique that uses both coherent and incoherent processing. Background is developed which relates the energy density function to the energy distribution function and the wide-band ambiguity function. The cross correlation of a signal’s energy distribution function is shown to be a convolution of its squared magnitude ambiguity function with the squared magnitude ambiguity function of the impulse response of the filter used to obtain the energy distribution functions. The output signal-to-noise ratio is derived for a single Doppler channel, assuming sampled, single-valued, energy distribution functions. The signal-to-noise ratio is also obtained, assuming amplitude spectral analysis, for the linear frequency modulated slide waveform.
Subject Classification: [43]60.20; [43]30.20; [43]28.20.
Cochlear nonlinearity and second filter: Possible mechanism and implications
Authors: Duifhuis H. 
Published: October 2005

We indicate that the directional sensitivity of the hair cell together with a directional distribution of frequency over the hair cells comprise a possible physiological basis for the second filter. Tuning disparity of the first and second filter denotes the difference in tuning frequency; at a given position x the tuning frequency of the first filter is αCF, of the second CF, with α≳1. This accounts for the asymmetry in location of two-tone suppression areas. The compressive nonlinearity is described by a νth law device with ν&lt;1. We analyze implications of this model for two-tone suppression, sharpening, pure-tone masking, and combination tone generation. Basic features of these phenomena are described adequately. For combination tones the propagation problem needs further study. On the basis of a comparison of literature data and theoretical predictions we estimate α=1.2 and ν=0.6. Regarding accurate shape of the first and second filter, the discussed data provide means for a qualitative evaluation only. Possibilities for a quantitative analysis are indicated.
Subject Classification: [43]65.20, [43]65.35, [43]65.42, [43]65.26.
Cavitation in liquid helium using a vibrating piston
Authors: Vroulis T. , Neppiras E. A. , Finch R. D. 
Published: October 2005

Experiments have been performed in which a piston is vibrated inside a glass tube containing liquid helium. The piston was driven by an electromagnetic shaker in the frequency range 20–80 Hz at an intensity capable of generating cavitation effects. At critical particle velocity amplitudes of a few centimeters per second noise is generated. This threshold velocity appears to be independent of frequency. A much higher velocity, about an order of magnitude greater, is required to produce visible bubbles in superfluid Helium II, but the two thresholds are the same in Helium I. The results are believed to indicate that fluid dynamic effects are important in cavitation nucleation.
Subject Classification: [43]25.60; [43]35.32, [43]35.47.
Dynamic effects of mechanical angular scanning of a parametric array
Authors: Widener M. W. , Rolleigh R. L. 
Published: October 2005

The effect of mechanical angular scanning of a parametric array is examined theoretically and experimentally. The results indicate that difference frequency pressure level and directivity are not affected if the frequency of rotation is small compared to the difference frequency.
Subject Classification: [43]25.35; [43]30.75.
Outdoor sound propagation over ground of finite impedance
Authors: Embleton T. F. W. , Piercy J. E. , Olson N. 
Published: October 2005

There is an extensive body of theory, and some laboratory measurements, of sound propagation over a surface of finite impedance. There are also reliable measurements of outdoor sound propagation in near-horizontal directions over the ground. In an attempt to relate these more closely, we have made carefully controlled measurements at ranges from 1 to 1000 ft, in most cases over grass-covered flat surfaces, to demonstrate the several phenomena that are involved. These phenomena depend on, and conversely provide a means of estimating, the values of ground impedance for waves at near-grazing angles of incidence. Such values obtained for grass-covered surfaces are in reasonable agreement with each other and with values obtained by conventional means at other angles of incidence. It is suggested that simple but accurate predictions of noise levels can be made by assuming that an excess attenuation due to finite ground impedance would always exist in a certain shadow region near the ground. This shadow region is however penetrated at low frequencies by a ground wave, to an extent that depends principally on distance and ground impedance, and at higher frequencies by interference between direct and ground-reflected waves to an extent that depends also on source and receiver heights. These phenomena, well established at ranges up to about 1000 ft and in some aspects to over 3000 ft, have been extrapolated theoretically to the order of 10 000 ft so that simple effects of topography and meteorology can be added to show how reflection or refraction acts in conjunction with ground impedance to result in penetration of the shadow region.
Subject Classification: [43]28.40; [43]20.55.
Effect of signal phase on the detectability of a tone masked by two tones
Authors: Phipps Alan R. , Henning G. Bruce 
Published: October 2005

The masking effect of two pure tones of equal intensity, started in phase, on a third pure tone placed midway in frequency between them was studied as a function of the frequency separation of the maskers for two different starting phases of the signal. At large separations (50 Hz or more), the signal phase had no effect on its detectability, but when the separation was smaller, the maskers were less effective at masking a signal which began in 90° phase with respect to the maskers than one which began in the same phase. These results are considered in terms of the energy-detector model frequently used to describe auditory processing; those at small separations are found to be inconsistent with such a device. It is suggested instead that deviations in the instantaneous frequency of the out-of-phase signal plus maskers complex are responsible for the improved performance with such signals when the bandwidth is small.
Subject Classification: [43]65.58, [43]65.60, [43]65.75.
Acoustic resonance in composite cavities
Authors: Hughes R. C. , Haering R. R. 
Published: October 2005

A treatment of the acoustic resonance of a composite cavity consisting of two intimately bonded one-dimensional acoustic cavities is given. We present an expression which can be numerically iterated to obtain the acoustic velocity from acoustic resonance measurements on a double cavity. A technique of evaluating the reflection coefficient of the bond interface of composite cavities is developed and it is shown that the particular metallic bond used in our experiments is nearly ’’perfect’’ acoustically. For a composite cavity consisting in part of a piezoelectric insulator, the electrical impedance and conductance are derived. Agreement between experiment and theory is good.
Subject Classification: [43]85.32; [43]20.40; [43]85.20.
Magnetomechanical characteristics of a terbium–holmium–iron alloy
Authors: Timme R. W. 
Published: October 2005

The magnetostrain, permeability, magnetostrictive constant, and elastic compliance constant of the alloy Tb0.145Ho0.855Fe2 have been measured as a function of magnetic bias. The magnetomechanical coupling constant and maximum power output calculated as a function of bias field are significantly higher than published values for nickel. The dynamic strain under power drive is as large as that of a commonly used ceramic at maximum drive. These findings support the conclusion that this ternary rare earth-iron alloy can compete with nickel or ceramics as a sound projector material.
Subject Classification: [43]85.46; [43]30.85.
Pronounced binaural pitch phenomenon
Authors: Bilsen Frans A. 
Published: October 2005

Using a special multiple-phase-shift filter with a flat amplitude response, a rather strong sensation of pitch was evoked by dichotic presentation of white Gaussian noise. The existence of this pitch, which resembles a periodicity pitch, can be understood on the basis of the ’’central spectrum’’ model of pitch perception [Bilsen and Goldstein, J. Acoust. Soc. Am. 55, 292–296 (1974)].
Subject Classification: [43]65.54, [43]65.62.
Perceptual features of speech for males in four perceived age decades
Authors: Hartman David E. , Danhauer Jeffrey L. 
Published: October 2005

Spontaneous speech samples of 46 male speakers between the ages of 25 and 70 years were played to 40 untrained listeners who estimated the speakers’ ages. Samples which showed agreement among untrained listeners were played to 20 trained listeners who described the perceptual features of the given perceived ages via a closed-response schema. Results showed characteristic perceptual features for four perceived age decades which could be classified according to pitch, rate of speech, quality, and articulation. The features were discussed in light of earlier findings. The features and their weightings by the listeners were derived from an a posteriori schema and samples of spontaneous speech. It was concluded that these features have perceptual importance and should be useful in establishing criteria for defining ’’normal’’ aging speech, planning management strategies for individuals with speech deviances, and in speaker recognition research.
Subject Classification: [43]70.30, [43]70.35.