Fastl, H. (1977). Roughness and temporal masking patterns of sinusoidally amplitude modulated broadband noise. In: Psychophysics and Physiology of Hearing (Evans, E.F., Wilson, J.P., eds.), Academic, London, 403-414
Acoustic roughness of sinusoidally amplitude modulated broadband noise was investigated. Roughness showed a bandpass characteristic for modulation frequency and decreased with decreasing modulation depth as well as SPL. For sinusoidally amplitude modulated broadband noise maskers, temporal masking patterns were determined by means of short test tone impulses. The level difference of maximal and minimal threshold value within these patterns showed a lowpass characteristic for modulation frequency and increased with modulation depth as well as SPL. Based on temporal masking data, a model for roughness was proposed. Roughness was found to depend both on the magnitude and velocity of the temporal masking pattern's variation. The model nicely fits the measured roughness data, in particular when the variance caused by the accuracy of measurement is taken into account. Since roughness of modulated broadband noise and AM-tones depends on stimulus parameters in the same manner, it is expected that the model accounts for the roughness of sounds with line spectra as well. The dependence of discharges of cells in the cochlear nucleus on modulation frequency, modulation depth and SPL was compared to the dependence of roughness on the same parameters. Despite some differences, interesting similarities could be demonstrated.