Narrow-band noise self-modulates at 0.64 times its bandwidth

Evidence

As narrow-band noise shows a self-modulation with an effective modulation frequency of 0.64 times the bandwidth, its fluctuation strength also depends on the bandwidth of the noise. In this demonstration, narrow-band noises with different bandwidths of 2, 6, and 50 Hz are presented. The noises have a center frequency of 1 kHz and a level of 70 dB. The largest fluctuation strength is reached for a noise with a bandwidth of 6 Hz producing an effective modulation frequency of about 4 Hz. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 3336

Categorization

• DEFINE: The 0.64-times-bandwidth factor is a precise, citable quantitative relationship linking noise bandwidth to perceived fluctuation.
• corroborated: 2 independent passages support this claim — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 3336
• XREF: connects to: Narrow-band noise behaves like a randomly amplitude-modulated pure tone.; Noise fluctuations within narrow critical bands raise the masking index; Random envelope fluctuations in 100-Hz-wide noise bands produce strong roughness — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1446 (+4 more)

Broader Connections

• Narrow-band noise self-modulation masks external amplitude modulation #expands (0.90) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 3302
• Time-delayed sound self-addition imposes spectral notches via autocorrelation #complicates (0.75)
• Narrow-band equalization causes audible ringing in the time domain #complicates (0.72)