Linda M. Thibodeau
Marc A. Fagelson
Dept. of Speech Commun., Univ. of Texas at Austin, Austin, TX 78712
Although much research has focused on the temporal, spectral, and intensity relationships between a masker and a suppressor, there has been little attention directed towards relative amounts of suppression in different frequency regions. The purpose of this experiment was to compare the magnitude of suppression at 500 and 2000 Hz in two forward-masking experiments with seven normal-hearing persons. In the first experiment, the threshold for a 10-ms probe was determined as the bandwidth of a 400-ms masker increased from 0.05 to 1.6 times the probe frequency. Suppression was determined by observing a decrease in threshold when the masker bandwidth exceeded the estimated critical band. In the second experiment, the threshold for a 10-ms probe was obtained with a 400-ms tonal masker in two conditions: masker-alone and masker+suppressor. Suppressor frequencies ranged from 1.1 to 1.5 times the probe frequency. Suppression was indicated by a lower threshold in the masker+suppressor condition relative to that in the masker-alone condition. In both experiments, the magnitude of suppression was smaller for the 500-Hz probe relative to the 2000-Hz probe.