Entwicklungslinien der Hörtheorie

Abstract

The human ear perceives acoustic vibrations within a great range of frequency and varying pressure which can be represented as the hearing area. Thecochlea in the inner ear acts as interface for mechanical, electrical and neural processes, and thus enables hearing.

In hisSensations of the Tone 1862 Hermann von helmholtz developed a resonance theory of hearing which states that sound of a distinct frequency sets only that part of the basilar membrane to mechanical resonance vibrations that is tuned to this frequency. First doubts concerning this explanation were expressed by Max wien in 1905.

Evidently, Helmholtz was unaware of the fact that a century ago Conte Giordano Riccati, a son of the mathematician Iacopo Riccati, had developed a partially similar hearing theory in his bookDelle corde ovvero fibre elastiche (1767). The resonance theory probably originates from a fundamental idea formulated by Philippe Rameau in hisGénération harmonique (1737).

Numerous measurements performed on ears post mortem by Georg von Békésy (1899–1972) revealed, however, that the frequency-to-place transformation is not caused by resonance but by traveling waves on the basilar membrane.

Lately Frank Böhnke has calculated analytically the traveling waves applying the Finite Element Method in his doctoral thesisWellenausbreitung auf der Basilarplatte des menschlichen Ohres (1992). His approach offers a promising alternative to measurements of the inner ear of human beings.