Corliss, E.L.R., Burnett, E.D., Stimson, H.F. (1968). "Polyacusis," a hearing anomaly. J. Acoust. Soc. Am. 43, 1231-1236
A previously unrecognized anomaly of pitch perception was discovered by H.F. Stimson while testing his hearing. Signals above 3500 Hz did not produce the same pitch in earch ear; the right ear's sensation was that of a sound at a lower frequency, for which he also had normal pitch perception. Between 3700 and 5200 Hz, the pitch perceived in the right ear was independent of the frequency of the stimulus. As intensity was raised, additional pitches appeared; and for an intense sound, a chord was heard whose constituents were not harmonically related. Stimson can match these anomalous pitches with sinusoidal stimuli of the appropriate lower frequency within about 2%; part of this variation is a change of pitch with intensity. Tones in his normal pitch range having a pronounced overtone structure are perceived as multiple. Overtones falling in the anomalous range give rise to the anomalous pitch. This would indicate a Fourier type of analysis before pitch recognition. Beats are not excited by interference between the pitches evoked by signals in the anomalous range and those heard normally. Loudness studies show signal powers to be additive. Tone-masking and loudness summation experiments yield data suggesting that the pitch recognition mechanism lies in that part of the auditory system in which loudness is perceived - i.e., beyond the cochlea.