Negative MLD's with Gated Sinewave Masking

Abstract

The detectability of S0 and Sπ signals, masked by a tone of the same frequency and duration, was measured as a function of the signal-masker phase. The signal and masker frequency was 250 Hz, and the duration 1/10 sec. In all conditions, Sπ signals were less detectable than S0 signals (a negative MLD), and this effect was largest (about 10 dB) with signal and musket in phase. Detection of S0 signals as a function of signal-masker phase closely follows the predictions of a simple energy detection model. The results with Sπ signals, however, are not consistent with any existing theory of binaural detection. In some general respects, the data suggest a mechanism similar to Durlack's equalization-cancellation mechanism. [Research supported in part by the National Institutes of Health, Public Health Service, U. S. Department of Health, Education and Welfare.]