The effects of specular versus diffuse room reflections on speech intelligibility

Classical speech intelligibility metrics are based primarily on signal-to-noise ratios and early-to-late energy ratios and do not consider room effects. This research investigates how room reflection type affects speech intelligibility. Subjects are presented binaurally with target sentences in the presence of interfering talkers in various simulated room conditions. These conditions include an anechoic room, large and small rooms with surfaces that provide diffuse reflections, and large and small rooms with surfaces that provide specular reflections. Subjects identified a significantly larger percentage of words correctly when the sentences were presented in the diffuse room conditions.