Strength of the pitches associated with ripple noise.

A discrimination procedure was used to measure the pitch strength of the repetition pitches associated with comb-filtered or ripple noise. Pitch strength was measured as a function of overall ripple noise level, the repetition pitch of the noise, and as a function of the center frequency of 1/3-octave bandpass filtered noise. In addition, other experiments were conducted to help determine which parameters should be used in measuring pitch strength when the discrimination procedure is employed. Pitch strength was strongest for pitches of approximately 500 Hz. The stimuli had essentially no pitch strength for pitches below 50 and above 2000 Hz. The strongest pitches were obtained when 1/3-octave filters were placed in a frequency region cented at four times the repetition pitch. Filtering at other center frequencies resulted in a large decrease in pitch strength. These results are consistent with assumptions concerning the dominant region for pitch perception of complex stimuli. The results are also discussed in terms of processing information from reflected sound sources.