Speaker
Description
Modeling speech intelligibility in spatially separated versus co-located masker conditions can reveal how listeners use spatial cues, such as interaural time and level differences, to separate speech from noise. Symmetric listening conditions, with maskers symmetrically positioned around a frontal target are particularly relevant because they approximate realistic situations with interfering sources evenly distributed around the listener and therefore do not provide a long-term signal-to-noise advantage at either ear. Binaural benefits arise solely from binaural unmasking (BU) and short-term better-ear (BE) listening.We used a modified binaural speech-based envelope power spectrum model to evaluate speech reception thresholds (SRT) and spatial release from masking (SRM) in symmetric two-masker conditions. The model analyzes envelope fluctuations of noise and noisy speech in short-time windows using three parallel processing pathways: two monaural pathways – one per ear – to simulate BE listening, and one binaural pathway that integrates information across ears via an equalization-cancellation process to simulate BU.Model predictions were compared with behavioral data across different spectro-temporal maskers in anechoic and reverberant symmetrical listening conditions. The model captured masker-dependent SRM effects for non-speech maskers in both anechoic and reverberant conditions. For speech-like maskers, it underpredicted SRTs and SRM in anechoic conditions and failed to capture SRM effects in reverberation, despite reproducing the SRT trends. We analyzed independent BE and BU simulations, evaluated their contributions, and compared the model’s predictions to those of other binaural models. Our findings underscore the importance of refining binaural models to account for realistic listening conditions, including reverberation and complex maskers, thereby improving our understanding of auditory speech processing in real-world acoustic environments.