Sound and Music

The periphery of the auditory system has received special attention from physiologists since 1870, when Helmholtz (with Hensen) proposed that the transverse fibers along the basilar membrane resonate selectively to different frequencies. There at last, it seemed, was a clear theoretical picture, in keeping with what was already known about the physical properties of resonators. However, this view had to be abandoned for various reasons. For one thing, the fibers are neither freely vibrating nor anatomically separate and because of that cannot mediate distinct perceptions of different frequencies. Second, the fibers vary greatly in length, but not in mass or tension; and although there are many of them (about 2800 over the seven octaves where discrimination is good), there are not enough to explain the subtlety attained by the musical ear. ¹ In fact, the idea of specific places of stimulation for different pitches has now been abandoned, without giving up the general idea of a place model of pitch perception altogether. The general notion has theoretical support (Blondel, 1934; Causse, 1944; Gribensky, 1951) and is approximately correct on a practical level: fibers in a specific region respond to a particular tone, with the region situated toward the basal end of the membrane for high tones and toward the apex for low tones (cf. van Esbroeck & Montfort, 1946; Wever, 1949). All the same, this approximation is not without difficulties, because it increases still more the number of fibers required to explain known discrimination abilities. Moreover, if an increase in intensity enlarges the region of stimulation, it ought to produce a decline in discrimination, but that is not the case. And the simultaneous perception of several neighboring tones at high intensity would be impossible because of the interference of the neighboring regions of stimulation.