Factors influencing temporal effects with notched-noise maskers

Temporal effects in simulataneous masking were studied by measuring the reduction in the amount of masking produced by a gated masker when that masker was preceded by a 400-ms noise (the precursor) that was usually spectrally identical to the masker. The signal frequency (fs) was 1.0 or 4.0 kHz. Experiment 1 revealed a temporal effect only when there was a spectral notch (centered at fs) in the masker and precursor. For a relative notchwidth of 0.4 fs, the temporal effect was larger at 4.0 than at 1.0 kHz. In experiment 2. where the masker and precursor both consisted of two bands of noise separated by a spectral notch of 0.4 fs, the size of the temporal effect remained essentially constant as the bandwidth of these noise bands increased from 0.2-0.8 kHz. The results from experiment 3 indicated that the temporal effect was largest when the level fo the precursor was equal to the level of the masker. Finally, the results from experiment 4 suggested that the temporal effect may depend upon the frequency region below as well as above fs, but that the frequency region above fs is probably more important.