Sharpness changes little with level and bandwidth below one critical band.

Evidence

Sharpness increases for a level increment from 30 to 90 dB by a factor of two. This means that the dependence on level can be ignored as a first approximation, especially if the level differences are not very large. Another small effect is the dependence on bandwidth, as long as the bandwidth is smaller than a critical band. No difference in sharpness can be detected whether one tone or five tones fall within one critical band or even when a critical-band noise is used for comparison. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1341

Categorization

• QUESTION: Is sharpness’s mild level dependence from 30 to 90 dB consistent across centre frequencies, or does it interact with the equal-loudness contours covered earlier?