Monaural and Binaural Free-Field Speech Reception through Ear-Level Hearing Aids under Noise and Reverberation

Abstract

Speech reception was studied in a room at reverberation times T = 0.3 and 0.6 sec, to compare binaural and monaural reception through ear-level hearing aids in the presence of a babble of eight voices. Some subjects (Ss) had normal hearing and some had severe sensorineural hearing impairment with bilaterally symmetrical audiograms. The speech and noise sources subtended an arc of 60° on a circle 11 ft in radius centered on the S's head. Binaural gain, the difference in speech to noise ratios for 50% correct speech reception comparing binuaral and monaural results, was 3 dB for normal Ss at both reverberant conditions. The binaural gain for impaired Ss varied from 3 dB to 0; those with previous binaural experience tended to show greater binaural gain. The prolongation of reverberation caused a reduction in reception. In presence of the masking noise, the reduction was about 15% correct response for both normal and impaired Ss. In quiet, normal Ss' reception was not influenced by the prolonged reverberation but the impaired Ss showed about 10% reduction in reception. [Supported by Gallaudet College].