Showing papers in "Journal of the Acoustical Society of America in 1968"
TL;DR: In this article, a combined Helmholtz Integral Equation Formulation (CHIEF) was proposed to obtain an approximate solution of the exterior steadystate acoustic radiation problem for an arbitrary surface whose normal velocity is specified.
Abstract: Three different integral formulations have been used as a basis for obtaining approximate solutions of the exterior steady‐state acoustic radiation problem for an arbitrary surface whose normal velocity is specified: (1) the simple‐source formulation, adapted from potential theory; (2) the surface Helmholtz integral formulation, based on the integral expression for pressure in the field in terms of surface pressure and normal velocity; and (3) the interior Helmholtz integral formulation, in which the surface pressure is determined by making a certain integral vanish for all points interior to the radiating surface. For certain characteristic wavenumbers, it is shown that no solution of the simple‐source formulation exists in general and that there is no unique solution of the surface Helmholtz integral formulation. The interior Helmholtz integral formulation is subject to similar difficulties and has undesirable computational characteristics. A Combined Helmholtz Integral Equation Formulation (CHIEF) that overcomes the deficiencies of the first two methods and the undesirable computational characteristics of the third, is described. The significant improvement over the previous three methods, which is accomplished through the use of CHIEF, is illustrated by numerical examples involving spheres, finite cylinders, cubes, and a steerable array mounted in two different boxlike structures.
986 citations
TL;DR: It is found that the presence of a second tone diminishes the responses to the first tone if appropriate stimulus parameters are chosen and all fibers tested showed this two‐tone inhibition.
Abstract: 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 tones or two tones presented simultaneously. We found that the presence of a second tone diminishes the responses to the first tone if appropriate stimulus parameters are chosen. All fibers tested showed this two‐tone inhibition. Response areas and inhibitory areas were defined from isorate contours. The general characteristics of the inhibitory areas are found to be similar for a population of over 300 fibers.
471 citations
TL;DR: Several methods of fundamental frequency and period measurement, based on these concepts, are described and the results of computer simulations and analog instrumentations indicate that these new methods compare favorably with, and in some cases exceed, the capabilities of cepstrum analysis.
Abstract: The fundamental frequency of a periodic signal whose fundamental component is not available for measurement can be determined by measuring the frequencies of its higher harmonic components and computing the largest common divider of these frequencies. Similarly, the fundamental period can be determined by measuring the periods of individual harmonics and finding their smallest common multiple. Several methods of fundamental frequency and period measurement, based on these concepts, are described in this paper. The results of computer simulations and analog instrumentations indicate that these new methods. at a considerable reduction in complexity, compare favorably with, and in some cases exceed, the capabilities of cepstrum analysis.
312 citations
TL;DR: The ability of listeners to locate sound in the vertical plane was investigated and showed that for auditory stimuli to be located accurately, the stimulus must be complex, it must include frequencies above 7000 cps, and the pinna must be present.
Abstract: The ability of listeners to locate sound in the vertical plane was investigated. The results showed that for auditory stimuli to be located accurately (1) the stimulus must be complex, (2) it must include frequencies above 7000 cps, and, (3) the pinna must be present.
292 citations
TL;DR: Although a relatively weak signal could inhibit the reaction to a subsequently presented intense signal, the effect was independent of the frequency characteristics of either signal.
Abstract: Several acoustic and temporal variables responsible for the elicitation of the rat's startle reaction were examined by measuring the subject's overt movement under each of a variety of stimulus conditions. When startle was repeatedly evoked, the response decreased in amplitude, but adaptation was slow and was not complete after 675 stimulus presentations. The threshold for startle evocation increased with repeated stimulation, but partial recovery occurred during interpolated rest periods. Startle reactions were amplified when testing occurred in a background of steady noise, but the effect was independent of the frequency components of the background stimulation. Moreover, although a relatively weak signal could inhibit the reaction to a subsequently presented intense signal, the effect was independent of the frequency characteristics of either signal. Finally, it was found that relatively weak signals could either inhibit the startle reaction to a subsequently presented intense signal or reduce response latency, depending upon the temporal relationships between the two signals. It was concluded that weak signals can activate the neural mechanisms responsible for the startle reaction, and that the occurrence of acoustic startle along with its associated inhibitory and facilitory effects is dependent upon the sensation levels of the signals, but not upon their frequency characteristics.
247 citations
TL;DR: It was found that captive rhesus monkey, chimpanzee, and gorilla's vocal mechanisms do not appear capable of producing human speech, and the data suggest that speech cannot be viewed as an overlaid function that makes use of a vocal tract that has evolved solely for respiratory and deglutitious purposes.
Abstract: Some representative vocalizations of captive rhesus monkey, chimpanzee, and gorilla were recorded and analyzed by means of sound spectrograms and oscillograms. It was found that these animals' vocal mechanisms do not appear capable of producing human speech. The laryngeal output was breathy and irregular. A uniform cross section, schwalike configuration appeared to underlie all the vocalizations. These animals did not modify the shape of their supralaryngeal vocal tracts by means of tongue maneuvers during a vocalization. Formant transitions occurred in some vocalizations, but they appeared to have been generated by means of laryngeal and possibly velar or lip movements. The nonhuman primates lack a pharyngeal region like man's, where the cross‐sectional area continually changes during speech. The data suggest that speech cannot be viewed as an overlaid function that makes use of a vocal tract that has evolved solely for respiratory and deglutitious purposes; the skeletal evidence of human evolution shows...
246 citations
TL;DR: A rubber replica has a pinna, concha, and auditory meatus with dimensions comparable with those of real human ears, and pressure distributions in the canal and concha are given for M1, M2, and three other modes.
Abstract: A rubber replica has a pinna, concha, and auditory meatus with dimensions comparable with those of real human ears. At the eardrum position, there is provision for a totally reflecting termination (hard wall) or for various eardrum impedance networks. The replica is mounted in a rigid plane, and a point source at a distance of 8 cm provides sound with various angles of incidence over the frequency range 1–15 kHz. The sound pressure is measured with a probe‐tube microphone at selected positions in the open canal and at the center of a plug closing the ear‐canal entrance (“meatus‐blocked” condition). The response with open canal and the response with blocked meatus have virtually identical angular dependence up to 12 kHz. From 2–7 kHz, there is substantial acoustic gain at the eardrum position associated with a fundamental canal resonance (M1) and a second mode largely controlled by a depth resonance of the concha (M2). Pressure distributions in the canal and concha are given for M1, M2, and three other modes. Limited data for six real ears with open and blocked canal are in good agreement with replica measurements up to 7 kHz. At 8 kHz, however, the on‐axis response of real ears passes through a sharp minimum that is either removed to a higher frequency or is largely absent with the sound source above the axis.
226 citations
TL;DR: Four experiments were conducted to develop and test a method of determining the frequency‐response characteristic of the observer when he listens for single‐frequency signals presented against a continuous background of wide‐band noise.
Abstract: Four experiments were conducted to develop and test a method of determining the frequency‐response characteristic of the observer when he listens for single‐frequency signals presented against a continuous background of wide‐band noise. After observers were trained to detect primary signals of a single frequency, probe signals of various other frequencies were presented infrequently, in lieu of the primary signal. Primary signals and all probe signals were presented with very similar amplitudes that would be expected to render them all equally detectable if presented alone in single‐frequency experiments. Estimates of the detectability of the signals of the various frequencies were obtained concurrently in a two‐alternative forced‐choice procedure. The results from 14 observers were quite similar and show differences in detection as a function of signal frequency when the primary signal was of 1000 or of 1100 Hz. In general, the primary signal was correctly detected 75%–90% of the time while signals with frequencies at approximately 150 to 200 Hz on either side of the primary‐signal frequency were detected at the chance level, 50% correct. In as few as three experimental sessions, the observer's frequency‐response characteristic was obtained using the probe‐signal method.
220 citations
TL;DR: Tone bursts of 1000 Hz with linear on and off ramps and plateaus of various durations were used to evoke cortical (vertex) potentials in five adult subjects and OFF responses showed similar relations but with smaller amplitudes and shorter latencies.
Abstract: Tone bursts of 1000 Hz with linear on and off ramps and plateaus of various durations were used to evoke cortical (vertex) potentials in five adult subjects. With 30 msec rise time, the amplitude, from N1 peak to P2 trough, and the latency to either the N1 peak or P2 trough were all independent of duration of the plateau from 0 to 300 msec. With 3 msec rise time, the amplitudes were progressively reduced when the plateau was shortened from 30 msec to 10, 3, or 0 msec. With a long plateau, the amplitudes were nearly constant for rise times of 50 msec or less. The latency of the V potential was prolonged at intensities of 45 dB (ISO) or less and also in relation to the slope of the onset ramp. With very gradual slope [300 msec to reach 45 dB (ISO)], mean latency to N1 was 169 msec while with very steep slope [3 msec to reach 85 dB (ISO)], it was 109 msec. OFF responses showed similar relations but with smaller amplitudes and shorter (by 16 msec) latencies. For evoked‐response audiometry, the rise time of the test signal will not be critical if it is 30 msec or less and the plateau is at least 30 msec long, and any plateau of 30 msec or longer will be acceptable.
220 citations
TL;DR: The notion that changes in stimulus frequency and increases in stimulus intensity activate new neural units was adopted to explain the data and it was asserted that habituation of the V potential is greatest when the same neural units are repeatedly activated and least when new Neural Unit brought into play.
Abstract: Interposed between periodic presentations of a 1000‐Hz tone were stimuli of different frequencies and intensities. The amplitude of the vertex (V) potential to the 1000‐Hz tone became larger as the frequency of the intervening stimuli departed progressively from 1000 Hz. It also became larger when the sensation level of the 1000‐Hz tone was raised progressively above that of the intervening stimuli. The notion that changes in stimulus frequency and increases in stimulus intensity activate new neural units was adopted to explain the data. It was asserted that habituation of the V potential is greatest when the same neural units are repeatedly activated and least when new neural units are brought into play.
220 citations
TL;DR: In this article, the threshold for subharmonic generation was calculated by means of a theory that relates the presence of the subharmonics to properties of Hill's equation, and it was found that the threshold is a function of the driving frequency and is a minimum for a given bubble, when the driving frequencies are approximately twice the linear resonance frequency of the bubble.
Abstract: Under proper conditions, bubbles driven by a sound field will pulsate periodically with a frequency equal to one‐half the frequency of the sound field. This frequency component is the subharmonic of order one‐half and is generated when the acoustic‐pressure amplitude exceeds a threshold value. The threshold for subharmonic generation is calculated by means of a theory that relates the presence of the subharmonic to properties of Hill's equation. It is found that, for a given bubble, the threshold is a function of the driving frequency and is a minimum when the driving frequency is approximately twice the linear resonance frequency of the bubble. In addition, solutions of a set of nonlinear equations for the motion of the bubble wall, obtained on a computer, illustrate the growth of subharmonics and are used to determine the steady‐state amplitude and phase of the subharmonic for a sequence of values of various parameters.
TL;DR: A family of reference signals for signal quality studies is described that is perceptually similar to speech signals undergoing certain signal‐dependent distortions, such as quantizing and predictive coding, which can yield greater accuracy and reproducibility in subjective comparison tests than do reference signals employing additive, signal‐independent noises.
Abstract: A family of reference signals for signal quality studies is described that is perceptually similar to speech signals undergoing certain signal‐dependent distortions, such as quantizing and predictive coding. This perceptual similarity can yield greater accuracy and reproducibility in subjective comparison tests than do reference signals employing additive, signal‐independent noises. Equally important, for nonstationary and the intermittent signals (such as speech) the signal‐to‐noise (S/N) ratios of the reference signals described here are defined on an instantaneous (sample‐by‐sample) basis, thus avoiding the troublesome ambiguities in measuring signal and noise powers. The distorted signal whose quality is to be evaluated can be assigned an equivalent S/N ratio independent of the time intervals over which average are extended.
TL;DR: It is found that tonal stimuli have intrinsic spatial characteristics, which result in the perception of frequencies with shorter periods as being higher in space than those with longer periods.
Abstract: Listeners, when requested to judge the location of tone bursts on the vertical plane, tended to place the stimuli on a vertical scale in accordance with their respective pitch. Higher‐pitched sounds were perceived as originating above lower‐pitched sounds. This phenomenon was also observed in congenitally blind persons and in young children who presumably were unaware of the use of the words high and low in describing differently pitched sounds. In additional tests, visual cues were found to influence the range of the scale within which listeners perceived the sound sources and they could even bias the location judgments of high‐pitched tone bursts despite contrary binaural cues. But the main implication of the data is that tonal stimuli have intrinsic spatial characteristics, which result in the perception of frequencies with shorter periods as being higher in space than those with longer periods.
TL;DR: In this paper, the spectrum of light inelastically scattered from density fluctuations is considered both for nonrelaxing and relaxing fluids, and the spectral distribution function has a somewhat more complicated form, but its interpretation is still quite straightforward.
Abstract: The spectrum of light inelastically scattered from density fluctuations is considered both for nonrelaxing and relaxing fluids. When the thermal conductivity of the liquid is small, the functions describing these spectra take on particularly simple forms. In addition to the unshifted Rayleigh line, caused by scattering from isobaric density fluctuations, the spectrum for a nonrelaxing liquid is just the response of a resonant system driven by thermal energy. For a relaxing liquid, the spectral distribution function has a somewhat more complicated form, but its interpretation is still quite straightforward. The use of electric circuit equivalents illustrates the principal features of the response spectrum. These results are formal ones, but while they are useful in understanding the scattering process, they are not particularly suited for the analysis of experimental results. For this purpose, approximations are developed that enable one to relate the out‐standing characteristics of the spectrum (for example, the positions and half‐widths of shifted lines) to fundamental relaxation parameters, such as the longitudinal storage and loss moduli.
TL;DR: In this paper, the authors present measurements of the acoustic emission from gas bubbles of controlled sizes "seeded" into water and glycerol-water mixtures and subjected to sound fields over a wide range of frequencies and intensities up to, and beyond, the transient cavitation threshold.
Abstract: This paper presents measurements of the acoustic emission from gas bubbles of controlled sizes “seeded” into water and glycerol‐water mixtures and subjected to sound fields over a wide range of frequencies and intensities up to, and beyond, the transient cavitation threshold. The emission from unprepared liquids was also recorded for comparison. A mechanical device has been developed for generating small bubbles of uniform sizes at controlled rates. The results suggest that there are at least two mechanisms for generating signals below the excitation frequency (f0): (1) Subharmonics of f0 may be produced by forced oscillations of bubbles whose radial resonance frequencies are submultiples of f0; (2) bubbles of any size may be shock excited to emit signals at their radial resonance frequencies. Large bubbles of certain preferred sizes are normally present, and their resonances probably account for many low‐frequency signals that are not integral submultiples of f0. It also seems certain that some other mec...
TL;DR: In this paper, the series impedance and shunt admittance of an acoustic line are calculated from the linearized acoustic equations, and exact and limiting formulas for small and large tubes are provided for R, L, G, C, the real and imaginary parts of the characteristic impedance Z 0, as well as the phase velocity v and attenuation constant α.
Abstract: The series impedance and shunt admittance of an acoustic line is calculated from the linearized acoustic equations. Exact and limiting formulas for small and large tubes are provided for R, L, G, C, the real and imaginary parts of the characteristic impedance Z 0, as well as the phase velocity v and attenuation constant α. All results are presented in convenient form for quick computation on the basis of tables and graphs. A self‐consistent set of molecular data is presented. Accuracies of formulas and of the data are discussed in detail.
TL;DR: In this paper, the authors derived an expression for the force exerted on a spherical bubble by the sound field, and experimental results were presented in support of the theory, and proved that the expression is correct.
Abstract: Bubbles can be trapped by a standing sound wave in a liquid. An expression is derived for the force exerted on a spherical bubble by the sound field, and experimental results are presented in support of the theory.
TL;DR: Masked thresholds were obtained for a bottlenosed porpoise at 15 frequencies between 5 and 100 kHz, using continuous broad‐band noise to mask tonal stimuli, compared to those from similar experiments with human subjects.
Abstract: Masked thresholds were obtained for a bottlenosed porpoise at 15 frequencies between 5 and 100 kHz, using continuous broad‐band noise to mask tonal stimuli. Critical bandwidths were calculated from the ratio of the tonal threshold level to the masking noise level per hertz at each frequency. At 5, 10, 20, 50, and 100 kHz, six different noise levels were used; from the resulting data, a plot of the amount of masking versus the effective noise level was obtained. The data are compared to those from similar experiments with human subjects.
TL;DR: The theory of Rayleigh scattering from density fluctuations is applied to data taken in glycerol and n-butanol over wide temperature ranges as discussed by the authors, which is useful in evaluating the viscoelastic parameters of a liquid when all corrections are properly applied.
Abstract: The theory of Rayleigh scattering from density fluctuations is applied to data taken in glycerol and n‐butanol over wide temperature ranges. It is shown that Brillouin scattering is useful in evaluating the viscoelastic parameters of a liquid when all corrections are properly applied. The position, half‐width, and intensity of the Brillouin lines as well as the total intensity are the main features of the spectrum used. The definition of the Landau‐Placzek ratio was generalized to be applicable to relaxing liquids and glasses and its behavior was studied over a 200°C temperature range in glycerol. The hypersonic data indicate that at high temperatures (∼70°C) in glycerol the distribution of relaxation times is narrower than that ultrasonically found at lower temperatures (∼−10°C). This result is in agreement with the concept that the origin of the distribution is related to cooperative behavior which is less pronounced at higher temperatures.
TL;DR: In this paper, the scattering of polarized harmonic shear waves by a sharp crack of finite length under antiplane strain is considered, and a method of integral transforms is used to reduce the problem to the evaluation of a system of coupled integral equations.
Abstract: The scattering of polarized harmonic shear waves by a sharp crack of finite length under antiplane strain is considered. Use is made of integral transforms, which reduce the problem to the evaluation of a system of coupled integral equations. Special emphasis is placed on obtaining the detailed structure of the crack‐front stress and displacement fields, which control the instability behavior of cracks in brittle materials. While the dynamic stresses around the singular crack point are found to be qualitatively the same as those encountered under statical loading, they differ quantitatively in that the intensity of the dynamical stress field, which may be regarded as a measure of the force tending to cause crack propagation, depends on the incident wavelength. At certain wavelengths, this intensification is shown to be larger than the static case. The method of solution in this paper applies equally well to boundary value problems in electromagnetic and acoustic theory.
TL;DR: In this paper, it was shown that the Simple Source Method, the Surface Helmholtz Integral Equation, and the Interior Hormone Integral Relation (IHE) all fail by nonuniqueness at the same frequencies.
Abstract: Attention has of late been drawn to the use of integral equations for obtaining numerical solutions to problems of steady‐state harmonic acoustic radiation. Essentially, three distinct methods have been reported: the Simple Source Method, the Surface Helmholtz Integral Equation, and the Interior Helmholtz Integral Relation. The present paper contains two major theoretical results. Firstly, nonexistence failure at certain frequencies of the simple‐source method is clearly indicated. Secondly, it is shown that the surface Helmholtz integral equation fails by nonuniqueness at the same frequencies. In both cases, failure occurs at each of the discrete Dirichlet eigenfrequencies for the region enclosed by the vibrating surface. Physical interpretations and examples of the theoretical results are included.
TL;DR: Results of a study of absolute threshold and duration‐of‐tone pulses in the bottlenosed porpoise indicated that the animal, in detecting pure‐tone stimuli, integrated the acoustic energy in essentially the same way as humans.
Abstract: Results of a study of absolute threshold and duration‐of‐tone pulses in the bottlenosed porpoise indicated that the animal, in detecting pure‐tone stimuli, integrated the acoustic energy in essentially the same way as humans. Pure‐tone thresholds were determined at 0.25, 1, 4, 20, 45, and 100 kHz for a wide range of pulse durations. Least‐squares fits to the data yielded time constants that were in general agreement with those obtained in experiments with humans. The data for very short pulses at 20 and 40 kHz indicated the presence of critical‐frequency bands, for which rough estimates were obtained.
TL;DR: A study of 1000‐Hz intensity discrimination is reported in which single tones were identified as the louder or softer of two alternatives differing slightly in energy, reflecting a form of energy discrimination similar to that proposed in noise masking.
Abstract: A study of 1000‐Hz intensity discrimination is reported in which single tones were identified as the louder or softer of two alternatives differing slightly in energy. Tones were phase locked and fixed in duration (150 msec). Feedback was given following each judgment. Psychometric functions are presented and a masking curve is computed. The masking curve is found to be linear above 25‐dB sensation level, and the slope is computed as 15/16. These results are interpreted as reflecting a form of energy discrimination similar to that proposed in noise masking.
TL;DR: In this article, an artificially blown and mechanically excited flute head joint is measured to provide values of the complex acoustic back pressure generated by the blowing jet, which is approximately twice the static blowing pressure times the ratio of the lip-to-edge distance and the velocity of propagation of a wave on the jet.
Abstract: Measurements on an artificially blown and mechanically excited flute head joint provide values of the complex acoustic back pressure generated by the blowing jet. The magnitude of the acoustic back pressure is calculable from the jet momentum and is approximately twice the static blowing pressure times the ratio of the lip‐aperture area to the tube cross‐section area. The phase of the induced back pressure relative to the oscillation volume velocity is determined by the lip‐to‐edge distance and the velocity of propagation of a wave on the jet. Adjustment of this phase is demonstrated to be the major means by which the flutist selects the desired mode of oscillation of the instrument. The efficiency of conversion from jet power to acoustic oscillation power is low (2.4% at 440 Hz) and is about equal to the ratio of particle velocities in the air column and the jet. Nonlinear (turbulent) losses are measured and are substantial. Stroboscopic views of the jet motion under explicitly stated oscillation conditions show the large amplitude of the jet wave and its phase relative to the stimulating acoustic disturbance.
TL;DR: Investigation of the ability of listeners to identify speaker sex from isolated productions of /f/, /θ/, /s/, and /∫/.
Abstract: A study was designed to investigate the ability of listeners to identify speaker sex from isolated productions of /f/, /θ/, /s/, and /∫/. Nine females and nine males recorded the four fricatives in isolation. The stimuli were randomized and presented via loudspeaker to 10 listeners for sex identifications. The results indicated that the listeners could identify the sex of the speakers from the isolated productions of /s/ and /∫/, but could not from the /f/ and /θ/ productions. Subsequent spectrographic analysis of the /s/ and /∫/ stimuli revealed that the female spectra tended generally to be higher in frequency than the male.
TL;DR: In this paper, the resonant properties of free, piezoelectric ceramic rectangular parallelepipeds, such as cubes, are investigated by means of the calculus of variations, the electroelastic differential equations are transformed into an approximate matrix characteristic value problem.
Abstract: This paper is concerned with the resonant properties of free, piezoelectric ceramic rectangular parallelepipeds, such as cubes. By means of the calculus of variations, the electroelastic differential equations are transformed into an approximate matrix characteristic value problem. Solution of this problem yields the resonant frequencies, the particle displacement patterns at resonance, and the equivalent circuit parameters such as the motional capacitances. Structures of the present type possess eight distinct symmetry families of modes; however, only one of these is excitable piezoelectrically with two opposite faces completely electroded. The resonant frequencies of the first 50 modes of this family are presented graphically versus Poisson's ratio for the special case of an isotropic cube. The frequency and dynamic capacitance of the first 30 modes of the same family are given for a piezoelectric ceramic square cylinder as the thickness‐to‐width ratio is varied from zero (thin square plate case) to uni...
TL;DR: The present paper outlines the historical background of the effect from the standpoint of its investigation and its application in electroacoustical systems.
Abstract: When two or more sound sources radiate identical or nearly identical complex signals, the listener hears a single image located at the nearer source, provided that the delay involved is between about 1 and 50 msec. This phenomenon (together with other closely associated aspects) is generally referred to as the “precedence effect” or “Haas effect.” Less frequently, the terms “law of the first wavefront,” “auditory‐suppression effect,” “first‐arrival effect,” and “threshold of extinction” have also been used in describing certain of these characteristics. Perhaps the earliest investigator to leave a clear record of his appreciation of the single‐image aspect of the phenomenon was Joseph Henry who, in 1849, used the term limit of perceptibility in describing what he had observed. The present paper outlines the historical background of the effect from the standpoint of its investigation and its application in electroacoustical systems.
TL;DR: 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, with response amplitude found to be a linear function of log10ISI.
Abstract: 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.
TL;DR: The stimulus‐evoked activity of single units in the left primary auditory cortex of cats immobilized with gallamine triethiodide was observed as tone bursts, noise bursts, or clicks were presented at a moderate intensity to the right ear, to the left ear, and simultaneously to both ears.
Abstract: The stimulus‐evoked activity of single units in the left primary auditory cortex (AI) of cats immobilized with gallamine triethiodide was observed as tone bursts, noise bursts, or clicks were presented at a moderate intensity to the right ear, to the left ear, and simultaneously to both ears. The right ear is represented more strongly in that more cells respond to monaural stimulation of the right ear than the left ear. An ear is said to be “represented” if a unit responds to stimulation of that ear, or if the response to stimulation of the other ear is modified by stimulation of that ear. There is extensive overlap of the populations of units representing the two ears; the population representing the left ear is almost completely contained within the larger population representing the right ear. The majority of units exhibited some form of binaural interaction. Binaural summation was the most common form of interaction; other units exhibited binaural inhibition or combinations of summation and inhibition.
TL;DR: The validity of a previously introduced psychophysical method of numerical magnitude balance applied to loudness scaling at low sound frequencies is discussed and the results are shown to agree with loudness‐matching data obtained in several investigations.
Abstract: The validity of a previously introduced psychophysical method of numerical magnitude balance is discussed The method is applied to loudness scaling at low sound frequencies The results are shown to agree with loudness‐matching data obtained in several investigations