Informational and energetic masking effects in the perception of multiple simultaneous talkers

Although many researchers have examined the role that binaural cues play in the perception of spatially separated speech signals, relatively little is known about the cues that listeners use to segregate competing speech mess ages in a monaural or diotic stimulus. This series of experiments examined how variations in the relative levels and voice characteristics of the targ et and masking talkers influence a listener's ability to extract informatio n from a target phrase in a 3-talker or 4-talker diotic stimulus. Performan ce in this speech perception task decreased systematically when the level o f the target talker was reduced relative to the masking talkers. Performanc e also generally decreased when the target and masking talkers had similar voice characteristics: the target phrase was most intelligible when the tar get and masking phrases were spoken by different-sex talkers, and least int elligible when the target and masking phrases were spoken by the same talke r. However, when the target-to-masker ratio was less than 3 dB, overall per formance was usually lower with one different-sex masker than with all same -sex maskers. In most of the conditions tested, the listeners performed bet ter when they were exposed to the characteristics of the target voice prior to the presentation of the stimulus. The results of these experiments demo nstrate how monaural factors may play an important role in the segregation of speech signals in multitalker environments. (C) 2001 Acoustical Society of America.