THE LACK OF FREQUENCY-DEPENDENCE OF THRESHOLDS FOR SHORT TONES IN CONTINUOUS BROAD-BAND NOISE

The threshold for detecting a tonal signal in a continuous broadband n oise increases with increasing signal frequency for long, but not for short signal durations. This is revealed by an analysis of previous st udies, and confirmed with three subjects in the present experiment usi ng signals covering a frequency range from 125 to 4000 Hz and a durati on range from 2 to 1000 ms. The relationship between threshold and sig nal frequency for a wide range of signal durations is explained by an energy-detector model in which the time window is assumed to match the signal duration and the predicted signal level is adjusted to compens ate for the loss of signal energy due to spectral spread at short dura tions. (C) 1996 Acoustical Society of America.