Spatial release from informational masking in speech recognition

Three experiments were conducted to determine the extent to which perceived separation of speech and interference improves speech recognition in the f ree field. Target speech stimuli were 320 grammatically correct but nonmean ingful sentences spoken by a female talker. In the first experiment the int erference was a recording of either one or two female talkers reciting a co ntinuous stream of similar nonmeaningful sentences. The target talker was a lways presented from a loudspeaker directly in front (0 degrees). The inter ference was either presented from the front loudspeaker (the F-F condition) or from both a right loudspeaker (60 degrees) and the front loudspeaker, w ith the right leading the front by 4 ms (the F-RF condition). Due to the pr ecedence effect, the interference in the F-RF condition was perceived to be well to the right, while the target talker was heard from the front. For b oth the single-talker and two-talker interference, there was a sizable impr ovement in speech recognition in the: F-RF condition compared with the F-F condition. However, a second experiment showed that there was no F-RF advan tage when the interference was noise modulated by the single- or multi-chan nel envelope of the two-talker masker. Results of the third experiment indi cated that the advantage of perceived separation is not limited to conditio ns where the interfering speech is understandable. (C) 2001 Acoustical Soci ety of America.