Abstract:

Psychophysical suppression was investigated across signal frequency (250, 500, 1000, 2000, and 4000 Hz) in a forward-masking paradigm. Masker duration was 200 ms, signal duration was 20 or 40 ms, and signal delay was 0 or 20 ms. When using a noise masker (spectrum level of 40 dB), the amount of suppression was determined by subtracting threshold in the presence of a broadband masker from that in the presence of a critical band masker. When using a tonal masker (masker level of 50 dB SPL, suppressor level of 70 dB SPL, with the suppressor frequency being 1.2 times the masker/signal frequency), the amount of suppression was determined by subtracting the threshold in the presence of the masker plus suppressor from that in the presence of masker alone. For both masker types, the amount of suppression increased as signal frequency increased up to 1000 Hz, but then reached an asymptote or decreased somewhat as signal frequency increased to 4000 Hz. [Work supported by NIDCD.]