The combined effects of reverberation and fluctuating noise on sentence intelligibility

Abstract

Listening conditions in everyday life typically include a combination of reverberation and nonstationary background noise. It is well known that sentence intelligibility is adversely affected by these factors. To assess their combined effects, a model is introduced that combines two models of speech perception, the Extended Speech Intelligibility Index (E-SII), and the Speech Transmission Index (STI). First, the effect of reverberation on nonstationary noise—reduction of modulations—is determined. The E-SII is then used to evaluate the effect of this modified nonstationary noise, while the STI is applied to quantify the effects of reverberation and noise on speech quality. To validate this model, speech reception thresholds (SRTs) were measured for ten normal-hearing listeners, under various combinations of nonstationary noise and artificially created reverberation. After taking the characteristics of the speech corpus into account, results show that the model accurately predicts SRTs in fluctuating noise and reverberation for normal-hearing listeners.