Abstract:
The detectability of a brief tonal signal was measured at various delays relative to the onset of a wideband noise masker. In simultaneous masking, there was complete temporal overlap between the masker and signal. In forward masking, the signal onset followed the masker offset, thus there was no temporal overlap. The overall level (50, 65, or 80 dB SPL) of the masker and the frequency (500 or 2000 Hz) of the signal were varied in conditions of both simultaneous and forward masking. Signal detectability in forward masking always improved as the delay between the masker onset (or offset) and signal onset increased. The change in signal detectability as a function of delay was more complicated in simultaneous masking. The detectability of 2000-Hz signals improved as the delay between the masker onset and signal onset increased. The magnitude of the effect, however, was greatest for mid-level maskers. Curiously, the detectabilityof 500-Hz signals worsened initially and then improved as the delay increased. [Work supported by NIDCD.]