Comparison of masking patterns for temporal and simultaneous masking

Abstract

Masking patterns were mapped under simultaneous and temporal masking conditions. In the first study, a 5-msec tonal signal was presented at various delays relative to onset of a 240-msec 80-dB tonal masker. Masked audiograms for the simultaneous (steady-state) masker conditions differed from temporal masking functions in two important respects. First, the classical upward-spread-of-masking effect was not observed in backward and forward masking. For example, at the secondary peak of the simultaneous masking function, the nonsimultaneous masker was nearly 30 dB less effective than the simultaneously presented masker. Second, for signal frequencies below the frequency of the masker, less masking was exhibited in the simultaneous masking condition. The temporal development of the masking pattern was investigated in a second study, in which the duration of the masker was varied. In the simultaneous-masker condition, in the region below the masker frequency, brief-duration maskers were as much as 20 dB more effective than long-duration maskers. In remote high-frequency regions, in both temporal and simultaneous masking, the brief-duration masker was as much as 15 dB less effective than the long-duration masker.