Speech intelligibility prediction of room with curved surfaces by means of its physical characteristics

Abstract

In the room, it was found previously that the ear uses the first arriving sound to locate the source, but the early reflections contribute to the intelligibility. Late reflections, on the other hand reduce intelligibility. Therefore, for speech intelligibility a high sound energy fraction is necessary, requiring high early energy and low late energy. Spatial impression which is the subjective effect of early sound reflections that come from the side walls and ceiling, contributes to the sense of envelopment. This paper presents the investigation of speech intelligibility with respect to the physical characteristics of rooms with curved surfaces. The investigated physical characteristics are source-to-listener distance (Lr), listener-to-the farthest wall (Lwmax), listener-to-the closest wall (Lwmin), listener-to-the farthest wall and listener-to-the average distance to walls (Lwave). In addition to objective acoustics measures such as reverberation time (RT60), early decay time (EDT), average sound absorption coefficient (Aave) and clarity (C50), speech intelligibility predictors STI and Alcons were also measured and analyzed. It is the intention of this paper to explore the possibility of predicting speech intelligibility performance of a room with curved surfaces by using its physical characteristics.