Using envelope modulation to explain speech intelligibility in the presence of a single reflection.

A single reflection is the simplest simulation of reverberation and provides insights into more complex scenarios of listening in rooms. This paper presents an analysis of the effects of a single reflection as its delay and intensity are systematically varied. The changes to the envelope modulations are analyzed using not only the traditional within-auditory-band analysis approach but also an across-band spectro-temporal analysis using cepstral correlation coefficients. The use of an auditory model allowed the extension of the simulations to include sensorineural hearing loss. Short delays did not interfere with the envelope modulations at low modulation rates (<16 Hz) and impact predicted intelligibility, while longer delays caused substantial distortion at these rates. The patterns of envelope modulation distortions caused by a single reflection were shown to be similar in models of normal hearing and hearing impairment.