Phonozoic Text Archive, Document 102

Helmholtz's Vowel Theory and the Phonograph

Nature, Vol. XVII, March 14, 1878, p. 384.

THE following experiments with the phonograph are of interest as throwing light on the nature of vowel sounds:--

            Let a set of vowel sounds as A, E, I, O, U (pronounced in Italian fashion) be spoken to the phonograph in any pitch, and with the barrel of the instrument turned at a definite rate.  Then let the phonograph be made to speak them, first at the same rate, and then at a much higher or lower speed.  The pitch is, of course, altered, but the vowel sounds retain their quality when the barrel of the phonograph is turned at very different rates.  We have made this experiment at speeds varying from about three to one, and we can detect no alteration in the quality of the sounds.

            According to Helmholtz, the characteristic quality of each vowel is given by the prominence of a constituent note or notes, of definite or approximately definite absolute pitch, in the sounds uttered.  Now obviously, the absolute pitches of the constituents of the vowel-sounds in the above experiment were all altered in the same proportion, so that the absolute pitch of the prominent notes varied greatly; but yet the vowel quality was unchanged.  This experiment, therefore, seems to give results in contradiction of Helmholtz’s theory as we understand it.

            At the same time we have found, in the course of experiments, of which a full account will shortly be communicated to the Royal Society of Edinburgh, that if a scale be sung to the phonograph with one vowel sound, such as O, the wave-form of the marks on the tinfoil does not remain unchanged at all pitches.  We have not yet had time to analyse the curves so obtained into their harmonic constituents.  Such an analysis will show whether the changes we have observed in the wave-form as the pitch rises, are due to a change in the relation of the amplitudes of the constituents present, or only to a variation of phase.



Edinburgh, March 11