On the Upper Cutoff Frequency of the Auditory Critical-Band Envelope Detectors in the Context of Speech Perception

Studies in neurophysiology and in psychophysics provide evidence for the existence of temporal integration mechanisms in the auditory system. These auditory mechanisms may be viewed as "detectors", parameterized by their cutoff frequencies. There is an interest in quantifying those cutoff frequencies by direct psychophysical measurement, in particular for tasks that are related to speech perception. In this study, the inherent difficulties in synthesizing speech signals with prescribed temporal envelope bandwidth at the output of the listener's cochlea have been identified. In order to circumvent these difficulties, signal processing rules have been formulated using a dichotic speech synthesis with interleaving smoothed critical band envelopes.