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Journal of the Acoustical Society of America

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Dec 1998

Volume 104, Issue 6, pp. 3138-3684

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Nonmonotonicity of informational masking

Eunmi L. Oh and Robert A. Lutfi

J. Acoust. Soc. Am. Volume 104, Issue 6, pp. 3489-3499 (1998); (11 pages) | Cited 35 times

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Neff and Green [Percept. Psychophys. 41, 409–415 (1987)] report that the masking of single tones by random-frequency multitone maskers varies nonmonotonically with number of masker components (peaking at 10–50 components). In this paper it is shown that such results are well predicted by a model (the component-relative-entropy model, CoRE) wherein thresholds increase linearly with the ensemble variance of masker spectra smoothed by peripheral auditory filters [R. A. Lutfi, J. Acoust. Soc. Am. 94, 748–758 (1993)]. Three experiments were conducted. In the first, the nonmonotonic relation was replicated for 9 of 11 listeners in conditions similar to those of Neff and Green. In the second, the frequencies of masker components were fixed and the levels of components were varied randomly across presentations to simulate Gaussian noise. In this case, the nonmonotonicity and the total amount of masking for these listeners were shown to be significantly reduced. In the third experiment, masked thresholds for the signal were found to vary monotonically with the frequency spacing of masker components for a fixed number of masker components. Large individual differences among listeners were obtained in some experimental conditions. Individual as well as mean thresholds were well predicted by the CoRE model with an appropriate selection of the values of the two free parameters of the model for each listener. © 1998 Acoustical Society of America.
Show PACS
43.66.Ba Models and theories of auditory processes
43.66.Dc Masking
43.66.Fe Discrimination: intensity and frequency

Suppression and the upward spread of masking

Andrew J. Oxenham and Christopher J. Plack

J. Acoust. Soc. Am. Volume 104, Issue 6, pp. 3500-3510 (1998); (11 pages) | Cited 31 times

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The purpose of this study is to clarify the role of suppression in the growth of masking when a signal is well above the masker in frequency (upward spread of masking). Classical psychophysical models assume that masking is primarily due to the spread of masker excitation, and that the nonlinear upward spread of masking reflects a differential growth in excitation between the masker and the signal at the signal frequency. In contrast, recent physiological studies have indicated that upward spread of masking in the auditory nerve is due to the increasing effect of suppression with increasing masker level. This study compares thresholds for signals between 2.4 and 5.6 kHz in simultaneous and nonsimultaneous masking for conditions in which the masker is either at or well below the signal frequency. Maximum differences between simultaneous and nonsimultaneous masking were small (<6 dB) for the on-frequency conditions but larger for the off-frequency conditions (15–32 dB). The results suggest that suppression plays a major role in determining thresholds at high masker levels, when the masker is well below the signal in frequency. This is consistent with the conclusions of physiological studies. However, for signal levels higher than about 40 dB SPL, the growth of masking for signals above the masker frequency is nonlinear even in the nonsimultaneous-masking conditions, where suppression is not expected. This is consistent with an explanation based on the compressive response of the basilar membrane, and confirms that suppression is not necessary for nonlinear upward spread of masking. © 1998 Acoustical Society of America.
Show PACS
43.66.Dc Masking
43.66.Ba Models and theories of auditory processes
43.66.Mk Temporal and sequential aspects of hearing; auditory grouping in relation to music

Profiling the perceptual suppression of partials in periodic complex tones: Further evidence for a harmonic template

Jeffrey M. Brunstrom and Brian Roberts

J. Acoust. Soc. Am. Volume 104, Issue 6, pp. 3511-3519 (1998); (9 pages) | Cited 6 times

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The basis for the perceptual cohesion of periodic complex tones was investigated. In experiment 1, 2–4 consecutive components (harmonics 6 and above) were removed from a 14-harmonic complex and replaced with a sinusoidal “probe,” located at one of a set of regularly spaced positions spanning the gap. On each trial, subjects heard a complex tone followed by an adjustable pure tone in a continuous loop. Subjects were better able to match the pure tone to the probe when the probe did not coincide with a harmonic position. Minima in “hit rate” were more pronounced when harmonic probes were in positions adjacent to other harmonics than when they were not. These findings suggest that the pitch of each in-tune partial was actively suppressed by a template whose influence attenuated with distance from regions of consecutive harmonics. In experiment 2, the partials on either side of the spectral gap were harmonics of different fundamental frequencies. Hit-rate minima corresponding to both fundamentals were found, indicating an upward and downward spread of suppression, and also demonstrating the concurrent operation of two templates. The results confirm recent findings in support of template models, and are consistent with the idea that partial-pitch suppression underpins harmonic fusion. © 1998 Acoustical Society of America.
Show PACS
43.66.Fe Discrimination: intensity and frequency
43.66.Hg Pitch
43.66.Ba Models and theories of auditory processes
43.66.Lj Perceptual effects of sound

Behavioral assessment of acoustic parameters relevant to signal recognition and preference in a vocal fish

Jessica R. McKibben and Andrew H. Bass

J. Acoust. Soc. Am. Volume 104, Issue 6, pp. 3520-3533 (1998); (14 pages) | Cited 5 times

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Acoustic signal recognition depends on the receiver’s processing of the physical attributes of a sound. This study takes advantage of the simple communication sounds produced by plainfin midshipman fish to examine effects of signal variation on call recognition and preference. Nesting male midshipman generate both long duration (>1 min) sinusoidal-like “hums” and short duration “grunts.” The hums of neighboring males often overlap, creating beat waveforms. Presentation of humlike, single tone stimuli, but not grunts or noise, elicited robust attraction (phonotaxis) by gravid females. In two-choice tests, females differentiated and chose between acoustic signals that differed in duration, frequency, amplitude, and fine temporal content. Frequency preferences were temperature dependent, in accord with the known temperature dependence of hum fundamental frequency. Concurrent hums were simulated with two-tone beat stimuli, either presented from a single speaker or produced more naturally by interference between adjacent sources. Whereas certain single-source beats reduced stimulus attractiveness, beats which resolved into unmodulated tones at their sources did not affect preference. These results demonstrate that phonotactic assessment of stimulus relevance can be applied in a teleost fish, and that multiple signal parameters can affect receiver response in a vertebrate with relatively simple communication signals. © 1998 Acoustical Society of America.
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43.66.Gf Detection and discrimination of sound by animals
43.80.Lb Sound reception by animals: anatomy, physiology, auditory capacities, processing

Effects of ear of entry and perceived location of synchronous and asynchronous components on mistuning detection

Hedwig Gockel and Robert P. Carlyon

J. Acoust. Soc. Am. Volume 104, Issue 6, pp. 3534-3545 (1998); (12 pages) | Cited 6 times

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Listeners were required to detect mistuning imposed on the center (“target”) component of a 200-ms complex consisting of the first seven harmonics of a 500-Hz fundamental. In the standard interval of each 2IFC trial, all components were frequency modulated in-phase by a 5-Hz sinusoid. In the signal interval the frequency modulation of the target component was inverted in-phase, thereby introducing a mistuning proportional to the depth of FM. In a similar experiment, using monaural presentation, Carlyon [J. Acoust. Soc. Am. 95, 2622–2630 (1994)] reported a substantial elevation of thresholds in the presence of an unmodulated asynchronous interferer with frequency identical to the mean frequency of the target. This was attributed to the interferer, causing the target component to be perceptually segregated from the remainder of the complex, thereby impairing across-frequency comparisons. Experiment 1 of the present study showed that an interferer presented contralaterally for 200 ms before and 100 ms after the signal complex (no simultaneous presentation) also impaired performance, but to a lesser extent than an ipsilaterally presented one. Experiment 2 showed that an interferer which was presented dichotically with an interaural level difference (ILD) of 10 dB, so that it was perceived contralaterally, had the same (large) effect as if it were presented ipsilaterally. Experiment 3 showed that, in the absence of any interferer, performance was impaired when the nontarget components were presented contralaterally to the target component. However, performance was not impaired when the nontarget components were presented dichotically with an ILD of 20 dB, so that they were perceived contralaterally to the target component. It is concluded that the level of performance in the mistuning task is determined by whether the target is presented to the same ear as the rest of the complex, rather than by its perceived location. © 1998 Acoustical Society of America.
Show PACS
43.66.Hg Pitch
43.66.Rq Dichotic listening
43.66.Mk Temporal and sequential aspects of hearing; auditory grouping in relation to music

On the source-identification method

William M. Hartmann, Brad Rakerd, and Joseph B. Gaalaas

J. Acoust. Soc. Am. Volume 104, Issue 6, pp. 3546-3557 (1998); (12 pages) | Cited 5 times

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The source identification method is a standard psychophysical procedure for studying the ability of listeners to localize the source of a sound. The method can be described in terms of a statistical model in which listeners’ responses are determined by the width and bias of an internal distribution. This article presents a theoretical study of the method, particularly the relationships between the average experimental observables, rms error and variability, and parameters of the internal distribution. The theory is tested against source-identification experiments, both easy and difficult. Of particular interest is the experimental dependence of observable statistics on the number of sources in the stimulus array, compared with theoretical predictions. It is found that the model gives a good account of several systematic features seen in the experiments. The model leads to guidelines for the design and analysis of source-identification experiments. © 1998 Acoustical Society of America.
Show PACS
43.66.Qp Localization of sound sources
43.66.Yw Instruments and methods related to hearing and its measurement
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