The effects of single and double hearing protection on the localization and segregation of spatially-separated speech signals.

Recent results have shown that auditory localization in the horizontal plane is dramatically worse for listeners wearing double hearing protection ~earplugs and earmuffs! than it is for listeners wearing single hearing protection ~earplugs or earmuffs alone!. This suggests that double hearing protection might also impair the spatial unmasking that normally occurs when two simultaneous talkers are spatially separated in azimuth ~the so-called ‘‘cocktail party’’ effect!. In this experiment, normal hearing listeners wearing no hearing protection, single hearing protection ~earmuffs!, or double hearing protection were asked to perform a speech intelligibility task that required them to segregate two simultaneous talkers who were either presented from the same loudspeaker or spatially separated by 90° in azimuth. The listeners were also asked to determine the location of the target talker in each trial. The results show that the listeners were unable to reliably determine the location of the target talker when they wore double hearing protection, but that they were still able to benefit from the spatial separation of the competing talkers. This suggests that the use of double hearing protection causes spatially separated sound sources to be heard at locations that are inaccurate but still distinct enough to enhance the segregation of speech. @DOI: 10.1121/1.1786812#