Bilsen, F.A. (1966). Repetition pitch: Monaural interaction of a sound with the repetition of the same, but phase shifted, sound. Acustica 17, 295-300
When a sound and the repetition of the same sound after a delay $\tau$ are presented together, monaurally, one perceives a "coloration", accompanied by a pitch sensation. This pitch, RP (Repetition Pitch), appears to correspond to the reciprocal $1/\tau$ of the delay time $\tau$. However, when all the frequency components of the delayed sound are shifted in phase by $90^\circ$, $180^\circ$ and $270^\circ$ resp., the RP changes to $1.07/\tau$, $0.88/\tau$ (or $1.14/\tau$) and $0.94/\tau$ resp. (In our case the sound was white noise, delayed by a tape recorder.) The same pitches are perceived when listening to a random sequence of pulse pairs (pulse distance $\tau$), where the first of (and) the second pulse is shifted in phase. These results cannot be explained simply by means of autocorrelation or frequency analysis.