Critical bandwidth varies a hundredfold across the audible range.

Evidence

At low frequencies, for example, the corresponding critical bandwidth is only 100 Hz wide, whereas at high frequencies near 10 kHz, the bandwidth is more than 2 kHz wide. Consequently, noise at high frequencies produces a steady-state condition, whereas noises at low frequencies produce a strong temporal modulation which hinders the process of hearing the interrupted test tone used in masking procedures. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 637

Categorization

• DEFINE: Concrete anchor for critical bandwidth magnitude — 100 Hz at low vs over 2 kHz at high frequencies — worth remembering as a reference figure.