Perceptual consequences of change in vocoded speech parameters for various reverberation conditions

The perceptual consequence of change in parameters of vocoded speech for various reverberation
conditions has been examined. The three controlled variables were: number of
bands, instantaneous frequency changes rate and reverberation conditions. The effects were
quantified in terms of: (a) non-words’ recognition scores for young normal-hearing listeners,
(b) “ease of listening” based on the time of reaction (response delay) and (c) the subjective
measure of difficulty (ten-degree scale). The results have shown that the fine structure information
is a relevant cue in speech perception in reverberation conditions. It has also been
observed that only the slow variations of instantaneous frequency are critical in perception.
A good correlation between all subjective measures considered was found in this study.