Speech intelligibility among modulated and spatially distributed noise sources

摘要

At a cocktail party, listeners are faced with multiple, spatially distributed interfering voices. Theuddominant interfering voice may change from moment to moment and, consequently, change in spatial location. The ability of the binaural system to deal with such a dynamic scene has not been systematically analyzed. Spatial release from masking (SRM) was measured in simple spatial scenes,udsimulated over headphones with a frontal speech source. For a single noise at 105°,ud, SRM wasudreduced if that noise modulated (10 Hz square wave, 50% duty cycle, 20 dB modulation depth), but,udfor two noises in symmetrical locations, SRM increased if the noises were modulated in alternation,udsuggesting that the binaural system can “switch” between exploiting different spatial configurations. Experiment 2 assessed the contributions of interaural time and level differences as a functionudof modulation rate (1–20 Hz). Scenes were created using the original head-related impulseudresponses and ones that had been manipulated to isolate each cue. SRM decreased steeply withudmodulation rate. The combined effects of interaural time and level differences were consistent withudadditive contributions. The results indicate that binaural sluggishness limits the contribution of binaural switching to speech understanding at a cocktail party