Spectral weighting in sound localization: Effects of competing noise

Abstract

The localization of complex sounds relies upon spatial cues, namely the interaural time differences (ITDs) and interaural level differences (ILDs) which are distributed across the frequency spectrum of the stimulus. Spectral weighting functions (SWFs) measured using free-field and binaural methods [Stecker et al., JASA 145, 1720 (2019)] have confirmed the spectral “dominance region” [Bilsen and Raatgever, Acustica 28, 131–2 (1973)] in which listeners utilize the ITD cue around 400-1000 Hz. However, the salience of the spectral “dominance region” in the presence of competing noise is unknown. Previous studies demonstrate decreased localization performance in the presence of a white-noise masker, especially when the stimulus does not contain high-frequency components [Lorenzi et al., JASA 105, 3454–3463 (1999); Brungart and Simpson, JASA 126, 3199–3208 (2009)]. The current study measures SWFs in the presence of two uncorrelated lateral white-noise maskers (at –90° and +90° azimuth) for three signal-to-noise ratios (SNRs: +9, 0, –6 dB). Contrary to our hypothesis that the “dominance region” would shift to higher frequency components, the “dominance region” remained salient around 400–1000 Hz across all SNRs. [Work supported by NIH R01-DC016643.]