Comodulation masking release (CMR) for multiple temporal envelope maskers

Abstract

Thresholds for a pure-tone signal were measured in masking noise composed of multiple noise bands. In some conditions, one group of flanking bands (consisting of half of the flanking bands) was comodulated, and independent of the other group of comodulated flanking bands in terms of temporal envelope. The center frequencies of the flanking bands were arranged such that noise bands from the two groups were spectrally interleaved. In these conditions, the band of noise centered on the signal was a combination of two noise bands, which were each comodulated with one group of flanking bands. CMR was obtained but was not of the magnitude observed when all noise bands shared a common temporal envelope. Potential cues in the multiple envelope maskers included the information in the summed representation of the flanking bands, and the degree of temporal envelope correlation between the on-signal band and the flankers. Additional stimulus conditions examined the viability of these cues. The results of these experiments support an envelope correlation explanation for the CMR observed with the multiple temporal envelope maskers. [Work supported by the Louisiana Board of Regents.]