Morgan, C.T., Garner, W.R., Galambos, R. (1951). Pitch and intensity. J. Acoust. Soc. Am. 23, 658-663
This paper presents data for changes of pitch with intensity for 18 ears, for frequencies from 125 cps to 8000 cps, and for intensities up to a loudness level of approximately 100 db. There are wide individual differences, but most observers show very small changes (less than 2 percent) of pitch with intensity. In general, as intensity is increased, pitch falls at low frequencies and rises at high frequencies. Two different methods of measuring pitch-intensity changes showed no significant difference.