Intensity discrimination of Gaussian-windowed tones: indications for the shape of the auditory frequency-time window.
The just-noticeable difference in intensity jnd(I) was measured for 1-kHz tones with a Gaussian-shaped envelope as a function of their spectro-temporal shape. The stimuli, with constant energy and a constant product of bandwidth and duration, ranged from a long-duration narrow-band "tone" to a short-duration broadband "click." The jnd(I) was measured in three normal-hearing listeners at sensation levels of 0, 10, 20, and 30 dB in 35 dB(A) SPL pink noise. At intermediate sensation levels, jnd(I) depends on the spectro-temporal shape: at the extreme shapes (tones and clicks), intensity discrimination performance is best, whereas at intermediate shapes the jnd(I) is larger. Similar results are observed at a higher overall sound level, and at a higher carrier frequency. The maximum jnd(I) is observed for stimuli with an effective bandwidth of about 1/3 octave and an effective duration of 4 ms at 1 kHz (1 ms at 4 kHz). A generalized multiple-window model is proposed that assumes that the spectro-temporal domain is partitioned into "internal" auditory frequency-time windows. The model predicts that intensity discrimination thresholds depend upon the number of windows excited by a signal: jnd(I) is largest for stimuli covering one window.
van Schijndel
N H
NH
Department of Otolaryngology, University Hospital VU, Amsterdam, The Netherlands.
Houtgast
T
T
Festen
J M
JM
D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D001309:Auditory Threshold; D006801:Humans; D008962:Models, Theoretical; D009622:Noise; D016011:Normal Distribution; D013997:Time Factors