A complete view of Acoustical Science & its bearings on music, for musicians & music students.

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Fig. 45.
This fact seems to show, that the ear has not the faculty of perceiving compound tones as such, but that it analyses them into their con­stituent partials. If this be the case, it follows that all compound sounds are formed by the union of two or more simple tones. Now it has been proved by Fourier, that there is no form of compound wave which cannot be compounded out of a number of simple waves, whose lengths are inversely as the numbers 1, 2, 3, 4, 5, &c. Musically, this proposition means, that every compound musical sound may be resolved into a certain number of simple tones, whose relative pitch follows the law of the partial tone series.
According to the theory of Helmholtz, briefly referred to in Chapter III, this analysis is effected by the ear as follows:— '' When a compound musical tone is presented to the ear, all those elastic bodies (that is, the radial fibres of the basilar membrane, and the corresponding arches of Corti) will be excited, which have a proper pitch corresponding to the various individual simple tones contained in the whole mass of tone, and hence by properly direct­ing attention, all the individual sensations of the individual simple tones, can be perceived."
A Simple Tone is one that cannot be analysed into two or more sounds of different pitch.