, Volume 33, Issue 4, pp 305-313

Effect and artifact in the auditory discrimination of rise and decay time: Speech and nonspeech

Abstract

The just noticeable difference (JND) for abruptness so far has not been studied in speech-like signals, and earlier studies have confounded decay time and overall signal duration. We therefore established JND for rise and decay time in a 10–80-msec range in a series of experiments involving an adjustment method using various speech and nonspeech signal types. Decay time did or did not vary independently of duration. Results showed that JND is in the order of 25%–30% of the reference value, with no essential difference between rise- and decay-time discrimination if these parameters are varied independently of duration. Decay-time discrimination turned out to be more accurate for wide-band signal types (noise) in the upper part of the stimulus range than it did for narrow-band signals (tones and complex harmonic signals). The data suggest that rise- and decay-time discrimination is too poor to reliably cue more than two categories in spite of the wide range of values found in speech sounds.