Psychophysical estimates of cochlear tuning using simultaneous and nonsimultaneous masking

Abstract

This study attempts to estimate the tuning of an auditory filter, through both simultaneous and forward masking experiments with a notched‐noise masker or a sinusoidal masker, to investigate how the effects of suppression affect estimates of frequency selectivity. In these experiments, masked thresholds of the short probe signal (5‐ms ramps, no steady state) centered in the masker or delayed from the masker were measured for normal‐hearing subjects as a function of the signal frequency (0.5, 1.0, 2.0, and 4.0 kHz), signal level (10, 20, and 30 dB SL), signal delay, and notch‐width conditions in the notched‐noise masker, or the masker frequency in the sinusoidal masker. ERBs were calculated from derived auditory filters to compare the cochlear tuning. The estimated tunings became much sharper as the center frequency was increased. Moreover, the difference between the tunings of the filter at lower frequencies with either form of masking tended to be smaller than that at higher frequencies. The tuning may be affected by residual effects of suppression due to lower masker components below the signal frequency. [Work supported by special coordination funds for promoting science and technology of young researchers from the Japanese Ministry of Education.]