Ernst Terhardt

Ernst Terhardt (born 11 December 1934) is a German engineer and psychoacoustician who made significant contributions in diverse areas of audio communication including pitch perception, music cognition, and Fourier transformation. He was professor in the area of acoustic communication at the Institute of Electroacoustics, Technical University of Munich, Germany.

Terhardt studied electrical engineering at the University of Stuttgart. His Master's thesis (Diplomarbeit) was entitled "Ein Funktionsmodell des Gehörs" (A functional model of hearing). His Dissertation was entitled "Beitrag zur Ermittlung der informationstragenden Merkmale von Schallen mit Hilfe der Hörempfindungen" (literally, "Contribution to determination of information-carrying characteristics of sounds with the help of auditory sensations"). Both projects were supervised by Eberhard Zwicker, with whom he founded the Institute for Electroacoustics, Technical University of Munich in 1967. Terhardt's Habilitation thesis (1972) was entitled "Ein Funktionsschema der Tonhöhenwahrnehmung von Klängen" (A model of pitch perception in complex sounds).

According to Terhardt’s theory of pitch perception, pitch perception can be divided into two separate stages: auditory spectral analysis and harmonic pitch pattern recognition. In the first stage, the inner ear (cochlea and basilar membrane) performs a running spectral analysis of the incoming signal. The parameters of this analysis (e.g. the effective length and shape of the analysis window) depend directly on physiology and indirectly on the co-evolution of ear and voice as our human and prehuman ancestors interacted with their social and physical environments. The output of this first stage is called a spectral pitch pattern, when it is determined by psychoacoustic experiments in which listeners make subjective judgments, matching the perceived pitch of a pure reference tone to that of a successively presented complex tone. The spectral pitches differ in perceptual salience since their sound pressure levels differ physically, they lie at different distances above the threshold of hearing, they mask each other (and therefore lie at different distances above the masked threshold), and may or may not lie in a region to which the ear is particularly sensitive (a dominance region of pitch perception). A cornerstone of Terhardt’s is approach is the idea that because spectral pitches are subjective, we must not jump to conclusions about the relationship between them and their physiological (physical) foundations in the ear and brain.

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