Hikaru Shoji

Critical band with respect to temporary threshold shift.

The existence of the critical band with respect to temporary threshold shift (TTS) was proved by the fact that TTSs, as a result of high‐pass and low‐pass filtered white noises, remained almost unchanged after they reached the certain value determined by the exposure time, irrespective of increase or decrease of the cutoff frequency of the exposure noises. Under the assumption that TTS becomes a linear function of a sound pressure level within the critical band, the center frequency and the width of the critical band for TTS at nine test frequencies (0.5, 0.8, 1, 1.5, 2, 3, 4, 6, 8 kHz) were calculated respectively from the data obtained by the narrow‐band noises and the noises whose spectrum level is a linear function of log2f. It was found that the center frequency of the critical band is about half an octave below the test frequency and that the width in decibels is about 6 dB larger than that of the critical masking band.