Guirao, M., Garavilla, J.M. (1976). Perceived roughness of amplitude-modulated tones and noise. J. Acoust. Soc. Am. 60, 1335-1338

Two sets of studies were conducted to determine the perceived auditory roughness of pure tones and narrow bands of noise modulated in amplitude. The signals used as carrier frequencies were 500- and 2000-Hz tones and two narrow bands of noise centered at the same two frequencies. Auditory roughness was measured by the psychophysical methods of magnitude estimation and a combination of magnitude estimation and magnitude production procedures. The average of the numerical estimates given by 10 Ss and the adjustments made by each one of the 40 Ss were plotted versus the degree of modulation $m=\Delta p/p$ of the SP. Results indicate that the perceived auditory roughness functions can be described by a power function with an average exponent of about 1.4. The exponent was about the same for the amplitude fluctuations of tones and noises.