Room and head coloration can induce obligatory stream segregation.

Multiple sound reflections from room materials and a listener's head induce slight spectral modifications of sounds. This coloration depends on the listener and source positions, and on the room itself. This study investigated whether coloration could help segregate competing sources. Obligatory streaming was evaluated for diotic speech-shaped noises using a rhythmic discrimination task. Thresholds for detecting anisochrony were always significantly higher when stimuli differed in spectrum. The tested differences corresponded to three spatial configurations involving different levels of head and room coloration. These results suggest that, despite the generally deleterious effects of reverberation on speech intelligibility, coloration could favor source segregation.