Signal and masker uncertainty with noise maskers of varying duration, bandwidth, and center frequency

Abstract

The detectability [human] of sinusoidal signals added to repeatable noise bursts was measured under conditions of signal-frequency uncertainty and masker-waveform uncertainty. Either source of uncertainty raised thresholds by 2-5 dB over those measured in a fixed-signal, fixed-masker condition, while the combination of both types of uncertainty raised thresholds by 8-12 dB. The magnitude of these elevations are similar to those found previously in which maskers composed of random sets of equal-amplitude tones were employed [Spiegel et al., 1981]. When masker level varied by up to 40 dB between the 2 intervals of a forced-choice trial, the signal thresholds were elevated by only 2.5 dB. A form of profile analysis is supported in which listeners detect signals by noticing a relative change in the masker spectrum.