William A. Yost

Bio: William A. Yost is an academic researcher from Arizona State University. The author has contributed to research in topics: Amplitude modulation & Acoustic source localization. The author has an hindex of 34, co-authored 193 publications receiving 5145 citations. Previous affiliations of William A. Yost include Loyola University Chicago & University of Florida.

The precedence effect.

Abstract: In a reverberant environment, sounds reach the ears through several paths. Although the direct sound is followed by multiple reflections, which would be audible in isolation, the first-arriving wavefront dominates many aspects of perception. The “precedence effect” refers to a group of phenomena that are thought to be involved in resolving competition for perception and localization between a direct sound and a reflection. This article is divided into five major sections. First, it begins with a review of recent work on psychoacoustics, which divides the phenomena into measurements of fusion, localization dominance, and discrimination suppression. Second, buildup of precedence and breakdown of precedence are discussed. Third measurements in several animal species, developmental changes in humans, and animal studies are described. Fourth, recent physiological measurements that might be helpful in providing a fuller understanding of precedence effects are reviewed. Fifth, a number of psychophysical models a...

Fundamentals of hearing: An introduction

Abstract: I. The Auditory Stimulus: Sound II. Peripheral Auditory Anatomy and Physiology III. Auditory Sensation IV. Auditory Perception, the Central Nervous System, and Auditory Disorders

A time domain description for the pitch strength of iterated rippled noise

Abstract: Two versions of a cascaded add, attenuate, and delay circuit were used to generate iterated rippled noise (IRN) stimuli. IRN stimuli produce a repetition pitch whose strength relative to the noise can be varied by changing the type of circuit, the attenuation, or the number of iterations in the circuit. Listeners were asked to discriminate between various pairs of IRN stimuli which differed in the type of network used to generate the sounds or the number of iterations (n=1, 2, 3, 4, 7, and 9). Performance was determined for IRN stimuli generated with delays of 2, 4, and 8 ms and for four bandpass filter conditions (0–2000, 250–2000, 500–2000, and 750–2000 Hz). Some IRN stimuli were extremely difficult to discriminate despite relatively large spectral differences, while other IRN stimuli produced readily discriminable changes in perception, despite small spectral differences. These contrasting results are inconsistent with simple spectral explanations for the perception of IRN stimuli. An explanation based on the first peak of the autocorrelation function of IRN stimuli is consistent with the results. Simulations of the processing performed by the peripheral auditory system (i.e., interval histograms and correlograms) produce results which are consistent with the involvement of these temporal processes in the perception of IRN stimuli.

Pitch strength of iterated rippled noise

Abstract: Two versions of a cascade add, attenuate, and delay circuit were used to generate iterated rippled noise (IRN) stimuli. IRN stimuli produce a repetition pitch whose pitch strength relative to the noise percept can be varied by changing the type of circuit, the attenuation, or the number of iterations in the circuit. Listeners were asked to use pitch strength to discriminate between various pairs of IRN stimuli which differed in the type of network used to generate the sounds, the number of iterations, and the attenuation in the network. A description based on an exponential function of the first peak of the autocorrelation function of IRN stimuli is consistent with the results. The discrimination data were well fit by a function based on the difference in the exponential functions of the first peak of the autocorrelation functions. A magnitude estimation experiment indicated that pitch strength was an exponential function of the height of the first peak in the autocorrelation function. These results suggest that the strength of the pitch of IRN stimuli is based on temporal processing as might be revealed by autocorrelation.

YIN, a fundamental frequency estimator for speech and music

Abstract: An algorithm is presented for the estimation of the fundamental frequency (F0) of speech or musical sounds. It is based on the well-known autocorrelation method with a number of modifications that combine to prevent errors. The algorithm has several desirable features. Error rates are about three times lower than the best competing methods, as evaluated over a database of speech recorded together with a laryngograph signal. There is no upper limit on the frequency search range, so the algorithm is suited for high-pitched voices and music. The algorithm is relatively simple and may be implemented efficiently and with low latency, and it involves few parameters that must be tuned. It is based on a signal model (periodic signal) that may be extended in several ways to handle various forms of aperiodicity that occur in particular applications. Finally, interesting parallels may be drawn with models of auditory processing.

Evolving conceptions of memory storage, selective attention, and their mutual constraints within the human information-processing system.

Abstract: The purpose of this review is to formulate a revised model of information processing that takes into account recent research on memory storage, selective attention, effortful versus automatic processing, and the mutual constraints that these areas place on one another. One distinctive aspect of the proposed model is the inclusion of two phases of sensory storage in each modality. The first phase extends sensation for several hundred milliseconds, whereas the second phase is a vivid recollection of sensation. The mechanism of at least the longer phase is the activation of features in long-term memory, comparable to the mechanism of non-sensory, short-term storage. Another distinctive aspect of the model is that habituation/dishabituation and central executive processes together are assumed to determine the focus of attention, without the need for either an early or a late attentional filter. Research issues that contribute to a comparison of models are discussed.

Informational and energetic masking effects in the perception of multiple simultaneous talkers.

Abstract: Although most recent multitalker research has emphasized the importance of binaural cues, monaural cues can play an equally important role in the perception of multiple simultaneous speech signals. In this experiment, the intelligibility of a target phrase masked by a single competing masker phrase was measured as a function of signal-to-noise ratio (SNR) with same-talker, same-sex, and different-sex target and masker voices. The results indicate that informational masking, rather than energetic masking, dominated performance in this experiment. The amount of masking was highly dependent on the similarity of the target and masker voices: performance was best when different-sex talkers were used and worst when the same talker was used for target and masker. Performance did not, however, improve monotonically with increasing SNR. Intelligibility generally plateaued at SNRs below 0 dB and, in some cases, intensity differences between the target and masking voices produced substantial improvements in performance with decreasing SNR. The results indicate that informational and energetic masking play substantially different roles in the perception of competing speech messages.

Neural processing of amplitude-modulated sounds.

Abstract: Joris, P. X., C. E. Schreiner, and A. Rees. Neural Processing of Amplitude-Modulated Sounds. Physiol Rev 84: 541–577, 2004; 10.1152/physrev.00029.2003.—Amplitude modulation (AM) is a temporal featu...