Speech intelligibility as a function of hearing aid microphone location

The contribution to speech intelligibility of the resonance effects of the ear canal and pinna has been of recent research interest. The present study investigated these effects by comparing monaural and binaural speech intelligibility between over-the-ear and in-the-ear microphone locations, utilizing a master hearing aid which controlled for other electroacoustic effects, The experimental design also allowed examination of the effects of azimuth on both monaural and binaural aided speech intelligibility. Items of the Tri-Word Test of Intelligibility [Sergeant et al., J. Acoust. Soc. Am. 65, 218–223 (1979)] were presented randomly from five loudspeakers equally separated on the front semicircle against an uncorrelated multiple-talker background. The results generally favored the in-the-ear microphone location. Binaural squelch was demonstrated.