Critical bandwidth stays constant near 100 Hz up to 500 Hz then grows

Evidence

Although the lowest critical bandwidth in the audible frequency region may be very close to 80 Hz, it is attractive to add the inaudible range from 0 Hz to 20 Hz to that critical band, and to assume that the lowest critical band ranges from 0 Hz to 100 Hz. Using this approximation, Fig. 6.8 shows the average of our data using five methods, more than 50 subjects, and levels between threshold in quiet and about 90 dB. Although there is a small tendency for the critical band to increase somewhat for levels above about 70 dB, the curve given in Fig. 6.8 represents a good approximation for critical bandwidth as a function of frequency. The critical bandwidth remains near 100 Hz up to a frequency of about 500 Hz. Above that frequency, the critical bandwidth increases a little slower than in proportion to frequency and for frequencies above about 3 kHz a little faster. It is useful to assume constant bandwidth of 100 Hz up to a centre frequency of 500 Hz, and a relative bandwidth of 20% for centre frequencies above 500 Hz. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 914

In this context, narrow-band noise means a noise with a bandwidth equal to or smaller than the critical bandwidth (about 100 Hz below and 0.2 f above 500 Hz, as outlined in Chap. 6). — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 415

Categorization

• DEFINE: Establishes the critical-band approximation rule (constant 100 Hz below 500 Hz, 20% relative bandwidth above) that future chapters rely on.
• corroborated: 2 independent passages support this claim — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 914; Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 415