THE GENERATION OF PSYCHOACOUSTIC COMBINATION TONES IN RELATION TO 2-TONE SUPPRESSION EFFECTS IN A COMPUTATIONAL MODEL

The amplitude of the psychoacoustic distortion product 2f(1)-f(2) elic ited by primaries f(1) and f(2) depends on the method of measurement. The cancellation-tone procedure gives consistently higher estimates of the distortion product than nonsimultaneous procedures. It was sugges ted that the difference could be attributed to suppression effects by the lower primary f(1) [Smoorenburg, J. Acoust. Sec. Am. 52, 615-632 ( 1972)]. Simulations carried out with a computational model of the audi tory periphery including a single, but distributed, compressive nonlin earity confirm the hypothesis; the amount of suppression produced at 2 f(1)-f(2) by f(1) equals the difference between simultaneous and nonsi multaneous methods of measuring the amplitude of the distortion produc t. This is in agreement with psychoacoustical data [Shannon and Houtga st, J. Acoust. Sec. Am. 68, 825-829 (1980)]. The model also reveals th e importance of suppression effects by f(1) to bring the phase of the traveling wave associated with the cancellation tone 2f(1)-f(2) in exa ct opposition with that of the distortion product 2f(1)-f(2) generated by the primaries. There is also evidence of suppression effects by th e higher primary f(2) when L-2 much greater than L-1. In the model, ca ncellation occurs over a substantial portion of the basilar membrane n ear the characteristic place for 2f(1)-f(2). (C) 1997 Acoustical Socie ty of America.