Detection and lateralization thresholds for repeated random waveforms in noise

Abstract

Interaural phase effects are reported for the lateralization and for the detection of repeated random waveforms in white noise. For lateralization, the primary component of interaural phase effects is the interaural phase of time-delayed signal and is relatively independent of the interaural phase of a nondelayed noise. In-phase signals yield substantially lower lateralization thresholds, at least for interaural delays up to 0.5–1.0 ms. This result is obtained with the following interaural noise relations: in phase, out of phase, random phase, and monaural noise. The importance of signal phase may relate to the search for moment-by-moment correlation by a binaural system with differential processing of waveform condensations and rarefactions. For detection, the primary component of interaural phase effects is related to the homophasic-antiphasic combination of signal and noise. The magnitude of the interaural phase effects is substantially smaller for wideband repeated random waveforms than reported for pure tones. The smaller interaural phase effects may relate to the difficulty of establishing lateralization cues for wideband signals in the absence of a time delay.