Sensitivity to across-frequency detection cues in binaural hearing

Abstract

The detectability of an Sπ signal in a narrow-band No masking noise can be improved by the addition of comodulated No flanking noise bands [Hall and Cokely, J. Acoust. Soc. Am. 83, 1839–1845(1988)]. This effect is relatively unreliable, however, occurring in only about 50% of listeners. The present study examined whether the effect can be made more reliable by slightly reducing the interaural correlation of the masking noise. For such a masker, interaural correlation fluctuates as a function of time. For the stimuli used here, the on-signal and the comodulated flanking bands shared the same pattern of interaural correlation as a function of time. The rationale was that the flanking bands could potentially be used as templates to help the auditory system distinguish the ongoing interaural differences of the slightly decorrelated on-signal noise band from the interaural differences introduced by the Sπ signal. Results from all six of the listeners tested showed improved Sπ detection in conditions where the on-signal and flanking bands had the same pattern of interaural correlation. This effect can be considered a form of binaural profile analysis wherein signal detection is aided by an across-frequency analysis of binaural cues. [Work supported by NIH NIDCD R01 DC00397.]