Pitch detection of dynamic iterated rippled noise by humans and a modified auditory model.

Iterated ripple noise (IRN) is a broadband noise with temporal regularities, which can give rise to a perceptible pitch. Since the perceptual pitch to noise ratio of these stimuli can be altered without substantially altering their spectral content, they have been useful in exploring the role of temporal processing in pitch perception [Yost, W.A., 1996. Pitch strength of iterated rippled noise, J. Acoust. Soc. Am. 100 (5), 3329-3335; Patterson, R.D., Handel, S.,Yost, W.A., Datta, A.J., 1996. The relative strength of the tone and noise components in iterated rippled noise, J. Acoust. Soc. Am. 100 (5), 3286-3294]. A generalised IRN algorithm is presented, in which multiple time varying temporal correlations can be defined. The resulting time varying pitches are perceptually very salient. It is also possible to segregate and track multiple simultaneous time varying pitches in these stimuli. Temporal auditory models have previously been shown to account for the perception of IRNs with static delays [Patterson, R.D., Handel, S.,Yost, W.A., Datta, A.J., 1996. The relative strength of the tone and noise components in iterated rippled noise, J. Acoust. Soc. Am. 100 (5), 3286-3294]. Here we show that some simple modifications to one such model [Meddis R., Hewitt, M.J., 1991. Virtual pitch and phase sensitivity of a computer model of the auditory periphery I. Pitch identification, J. Acoust. Soc. Am. 89, 2866-2882] allow it to track moving correlations, and also improve its performance in response to static correlations.