Relationship Between Localization Acuity and Spatial Release from Masking

Background/Objectives: Spatial hearing enables listeners to segregate competing sound sources in complex acoustic environments. Two key components of spatial hearing are localization acuity and spatial release from masking (SRM). Although both rely on similar binaural cue processing, their relationship remains unclear. The present study aimed to investigate localization acuity using frequency-specific and broadband stimuli and to determine how these measures relate to SRM in young normal-hearing listeners. Methods: Forty-five normal-hearing participants completed free-field localization and speech identification tasks using a multi-loudspeaker array. Localization acuity was assessed using one-third octave low-frequency (500 Hz), high-frequency (5000 Hz), and broadband noise stimuli. SRM was measured using a Coordinate Response Measure (CRM) speech task under colocated and spatially separated conditions (±30°). Localization performance was quantified using percent correct and root-mean-square (RMS) error, and relationships between localization acuity and SRM were examined using correlation analyses. Results: Localization performance varied significantly with stimulus bandwidth, with broadband stimuli yielding the highest accuracy, followed by low- and high-frequency conditions. Listeners demonstrated robust SRM (~5.6 dB). Moderate negative correlations were observed between RMS error and SRM across all stimulus conditions. Although the broadband condition yielded numerically larger correlation coefficients, differences among correlations were not statistically significant. Conclusions: Localization acuity was moderately associated with SRM across stimulus conditions. Although numerically larger correlations were observed for broadband stimuli, these differences were not statistically significant. The findings suggest that localization acuity represents one of several factors contributing to spatial hearing performance in complex listening environments.