Narrow-band noise produces substantial loudness in critical-band regions where no physical sound exists

Evidence

The distribution of specific loudness as a function of critical-band rate is not so simple for the narrow-band noise. It is plotted in Fig. 8.16 in the lower right diagram. The area below the specific loudness pattern again corresponds to total loudness. This area, however, is concentrated not only in that region in which the narrow-band noise is physically present, but also shows slope-specific loudnesses towards lower, and especially towards higher critical-band rates. The dashed area indicates clearly the large amount that contributes to the total loudness in the area of critical-band rates above 9.5 Bark. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1256

Categorization

• QUESTION: The 9.5 Bark cutoff seems specific — is there a physiological reason (basilar membrane asymmetry beyond that rate) or is it stimulus-dependent?