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Detection of interaural delay in high-frequency sinusoidally amplitude-modulated tones, two-tone complexes, and bands of noise

1994; Acoustical Society of America; Volume: 95; Issue: 6 Linguagem: Inglês

10.1121/1.409973

1520-9024

Leslie R. Bernstein, Constantine Trahiotis,

Advanced Electrical Measurement Techniques

Listeners’ ability to detect interaural temporal disparities (ITDs) was investigated for 160-ms, sinusoidally amplitude modulated (SAM) tones, two-tone complexes, and bands of noise at center frequencies of 4, 8, or 12 kHz. Rates of modulation for the 100%-modulated SAM tones and frequency separation for the equal-amplitude, two-tone complexes ranged from 32–768 Hz, depending on center frequency. Noise bandwidths ranged from 50–2000 Hz, also depending on center frequency. The data indicate, consistent with previous results, that sensitivity to ITD with the SAM and two-tone complexes decreases as the rate of envelope fluctuation increases beyond about 400 Hz. The decline in performance is not due simply to reduced depth of modulation produced by critical-band-like filtering, but is consistent with an inability to ‘‘follow’’ or encode high rates of modulation. For bands of noise, sensitivity to ITD was relatively constant as a function of bandwidth. Generally, sensitivity to ITD decreased as center frequency was increased from 4 to 8 kHz, but the relations among the data were essentially unchanged. Increasing the center frequency to 12 kHz resulted in very poor performance.