Effect of temporal gaps on informational and energy-based masking

Abstract

The effect of a temporal gap on detecting a 1000-Hz tone in the presence of 60-dB SPL simultaneous maskers was examined. Ten-component, random-frequency maskers and broadband-noise maskers were used in a 2-AFC adaptive task. Random-frequency components were drawn from 300 to 3000 Hz, excluding a 160-Hz band around the signal. Temporal gaps of 10, 20, 40, 80, and 160 ms were tested, positioned either at the onset, center, or offset of either the signal or the masker. Without gaps, both signal and masker durations were 200 ms. To maintain equal energy across all conditions, level compensation was applied when gaps were employed. For temporal gaps in either the multicomponent or noise masker, masked thresholds consistently decreased as gap duration increased. Gaps in the masker appeared to provide a temporal window for detection of the signal. However, for gaps in the signal, masked thresholds decreased with the multicomponent masker, but remained constant with broadband noise masker. With multicomponent maskers, the gaps appeared to reduce informational masking by perceptually segregating the signal from the masker. With broadband noise maskers, there was little informational masking and therefore the temporal gaps did not improve performance. [Work supported by NIDCD.]