The existence region of Huggins' pitch

Huggins' pitch (HP) can be heard when listening to white noise which is diotic at all frequencies except for a narrow band over which the interaural phase of the noise changes progressively through 360 degrees. The detectability (d') of HP was measured for 11 center frequencies between 100 Hz and 3200 Hz in half-octave steps. The listeners' task was to discriminate HP stimuli from diotic noises in a single-interval, YES/NO task. Detectability was simultaneously compared with that of pure tones presented interaurally out of phase and masked by diotic white noise (NoS pi). The levels of the tones were set so that they would fall below masked threshold monaurally at the higher frequencies tested. All four listeners showed similar patterns of detectability at high frequencies for both the Huggins-pitch stimuli and the masked tones. The results showed that HP can be detected at higher frequencies than previously reported; all four listeners could detect both the tones and HP to some extent at 2256 Hz and one listener could also detect HP at 3200 Hz. The results demonstrate that both HP and NoS pi stimuli show a sharp drop in detectability at around 1500 Hz, but remain detectable at higher frequencies.