Impacts of component audibility and noise masking on spectral weighting of sound-localization cues

Spatial localization of complex sound requires appropriate integration of acoustic cues across the frequency spectrum. Spectral weighting functions (SWFs), which quantify the relative weighting of cues across frequency components, have been measured through binaural and free-field methods using observer weighting techniques adapted from Stecker and Hafter [J. Acoust. Sci. Am. 112, 1046–1057 (2002)]. SWFs obtained with equal-amplitude components support a “dominance region” around 400–800 Hz [Bilsen and Raatgever, Acoustica 28, 131–132 (1973); Stecker and Folkerts, J. Acoust. Sci. Am. 145, 1720 (2019)]. The current study extends this work to compare the effects of component intensity on SWFs of stimuli presented with competing noise and stimuli filtered through a high-frequency sloping hearing-loss simulation (HLS). Localization with a white-noise masker deteriorates more for low-frequency than high-frequency noise stimuli [Abel and Hay, Scand. Audiol. 25, 3–12 (1996); Lorenzi et al., J. Acoust. Sci. Am. 105, 1810–1820 (1999)]. Imposition of spectral slopes introduced “level dominance” [Berg, J. Acoust. Sci. Am. 88, 149–158 (1990); Lutfi and Jesteadt, J. Acoust. Sci. Am. 120, 3853–3860 (2006)] in the form of increased weights for the loudest components. Weighting pattern changes in the presence of noise and similar patterns with the HLS due to “level dominance,” if confirmed, may impact spatial hearing by shifting the dominance region. [Work supported by NIH R01-DC016643.]