White noise shows frequency-flat long-term spectra but frequency-dependent short-term spectra

Evidence

White noise is an important example of a sound producing a continuous spectrum. In psychoacoustics, for practical reasons, the bandwidth of the white noise is normally limited to 20 Hz-20 kHz. As can be seen in the panel “white noise” in Fig. 1.1, the spectral density is independent of frequency in the whole range of 20 kHz. It should be mentioned that this holds for the long term spectrum, whereas the short term spectrum of white noise may show some frequency dependence. The time function of white noise exhibits a Gaussian distribution of amplitudes. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 82

Categorization

• DEFINE: Defines white noise in psychoacoustic terms and flags the long-term versus short-term spectrum distinction.