Noise bandwidth changes sharpness dramatically across a wide range

Evidence

Increasing the upper cut-off frequency from about 300 Hz increases sharpness continuously and, when plotted on the scales of Fig. 9.1, along an almost straight line between 0.3 and 2.5 acum. … Decreasing the lower cut-off frequency of this noise band decreases sharpness. The decrement reaches a factor of about 2.5 when the lower cut-off frequency is decreased to 1 kHz. For further reduction of the cut-off frequency, sharpness remains almost constant, provided the overall loudness is kept constant. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1349

The difference in sharpness between a narrow-band noise at 1 kHz, a uniform exciting noise, and a high-pass noise with 3 kHz cut-off frequency is demonstrated. In accordance with data displayed in Fig. 9.3, sharpness increases from narrow-band noise over broad-band noise to the high-pass noise. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 3332

Categorization

• corroborated: 2 independent passages support this claim — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1349; Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 3332