Effect of contralateral and ipsilateral noise on the quality of monaural speech

Abstract

This study was carried out to examine certain effects of ambient noise on the quality of speech communication over telephone channels. The stimuli consisted of monaurally presented speech and accompanying circuit noise and binaurally presented background noise. The background noise and the circuit noise had identical spectral characteristics. The stimuli were presented over headphones for good stimulus control. The ambient noise was represented by background noise which remained constant over a block of trials. The variables manipulated over trials were speech level, circuit noise level, and the ipsilateral and contralateral background noise. On each trial subjects heard two phonetically balanced sentences and were asked to respond on a ten-point quality rating scale. The data were analyzed in terms of averages of the ratings. This analysis indicates that the circuit noise is more detrimental to the quality judgments than the identical level of ipsilateral background noise although the two noises have identical physical characteristics. In addition, as expected from contralateral masking studies, the contralateral background noise has only minimal effect on the ratings compared to the ipsilateral noise.