Comparisons of measures of speech intelligibility in rooms

Abstract

The speech transmission index, useful-to-detrimental ratios, and percent articulation losses are three quite different types of measures of speech intelligibility in rooms. They each combine a measure of the speech-to-noise ratio and a room acoustics measure to better relate to speech intelligibility. Variations of all three types of measures were calculated from 91 impulse responses obtained from a wide range of acoustical conditions, and for different speech-to-noise ratios. Several broadband forms of these measures are shown to be reasonably well related to each other. The results are used to derive conversion equations between the three types of measures.