van den Brink, G. (1970). Two experiments on pitch perception: Diplacusis of harmonic AM signals and pitch of inharmonic AM signals. J. Acoust. Soc. Am. 48, 1355-1365
In the first experiment, binaural diplacusis for harmonic three-component (amplitude-modulated) signals has been measured. There appears to be a good agreement between diplacusis for complex signals and the average of the pure-tone diplacusis for its spectral components. In all cases, the pitch of the stimuli used roughly agreed with the pitch of the common, but nonexistant, fundamental. Apparently, the pitch of the separate components is more important than their frequency. Conclusively, the origin of binaural diplacusis cannot be found in a peripherally located mechanism, but in some higher center. In the second experiment, the pitches of inharmonic amplitude-modulated signals were matched monaurally with those of harmonic signals. The experiment gives direct quantitative information of the pitch deviations which have been found regarding the time-fine-structure theory. These deviations increase progressively with the rate of inharmonicity of the signal and decrease with decreasing intensity and modulation depth. The results suggest that the deviations are due to neural interaction mechanisms and thus can not be described in simple mathematical formulas.