Abstract:
The pitch strength of iterated rippled noise (IRN) was investigated in a pitch strength discrimination experiment. IRN is generated by a cascade of an add, delay (d in ms), and attentuate (g) circuit, where n represents the number of iterated stages in the circuit. In this study g was negative, which represents the cases in which the noise is subtracted rather than added. IRN produces a pitch, which when n is negative is either ambiguous with a pitch near 10% of the reciprocal of the delay, d, or at one over twice the delay, d. The strength of the pitch varies with g,n, and the type of circuit. Listeners were asked to discriminate between two IRN stimuli each generated with the same d, but with different values of g, and n, and different types of circuits. The discrimination results could only be accounted for by using the first peak in the autocorrelation function of these stimuli. The results will be discussed in terms of recent computational models of pitch processing. [Work supported by NIDCD and AFOSR.]