PERCEPTION OF TIMBRE. ANALYSIS OF VOWELS. 905 



Analysis of the Vowels. The human larynx represents a wind-instru- 

 ment, with vibrating, elastic reeds (vocal bands). In producing the 

 various vowels, the mouth assumes a characteristic form, so that its 

 cavity sustains a definite fundamental tone, which is produced when 

 the air passes into it from the larynx. In this manner certain over- 

 tones are added to the fundamental tone produced by the larynx, and 

 they give to the voice the vocal quality. The vowel-sound, therefore, 

 is the timbre of a musical sound produced by the larynx. The timbre 

 depends upon the number, strength and pitch of the overtones, and \ the 

 latter depend upon the configuration of the vocal-cavity in producing 

 the various vowels. 



If the different vowels are sung one after the other in a definite pitch, for ex- 

 ample b, it can be determined with the aid of the resonators what overtones are 

 added to the fundamental tone, and in what strength. According to v. Helm- 

 holtz, if the note b is sung, there is one characteristic overtone of definite, absolute 

 pitch for three vowels, namely b 11 for A; b 1 for O, and f for U. The other vowels 

 (and, in German, the modified vowels) have each two especially characteristic 

 overtones, because the oral cavity is so shaped, while producing them, that there 

 is a fundamental tone both for the posterior, more capacious portion, and for the 

 anterior, narrow portion (I and E, p. 612). According to v. Helmholtz these 

 two overtones are for E, b m and f 1 ; for I d iv andf; for A g m and d 11 : for 6, 

 cis 111 , and f 1 ; for U g in and f. These are, however, only the especially character- 

 istic overtones. Fundamentally there exist for the vowels almost generally many 

 others, which, however, are considerably less conspicuous. 



Thus the partial tones present in the same absolute pitch are always charac- 

 teristic of the vowels; according to v. Helmholtz, Hensen, Pipping and others, 

 they are harmonic overtones of the note of the vocal bands strengthened by 

 resonance. According to Hermann the overtone is an independent note produced 

 in the oral cavity, and it need have no harmonic relation with the sound produced 

 by the larynx. 



Just as it is possible to resolve a vowel into its fundamental tone and overtones 

 by means of resonators, so the vowel can be reproduced by sounding together 

 the strong fundamental tone and the weaker overtones. This may be done in 

 the following ways: (i) Most simply by singing loudly a vowel, for example A, 

 at a certain pitch, into an open piano against the free strings, while the damper 

 is at the same time raised by the pedal. If the voice suddenly ceases, the vowel 

 is sounded by the strings of the piano. In other words, all those strings are set 

 into sympathetic vibration whose overtones (apart from the fundamental tone) 

 occur in the vowel-sound. They continue to sound, therefore, for some time 

 after the voice has been interrupted. This experiment may be modified by raising 

 the damper from those notes only that occur as overtones (by holding down the 

 keys). In this way it is possible to combine the vowel-sound, note for note. 



(2) The vowel-apparatus of v. Helmholtz consists of a number of tuning-forks, 

 which are kept in constant vibration by electromagnets. The lowest fork yields 

 the fundamental tone B, the others in succession the overtones. In front of each 

 fork there is placed a resonance-tube, which can be opened and closed by a lid. 

 When the tube is closed, the tone of the corresponding tuning-fork cannot be 

 heard, but when one or more of the tubes are opened their notes are heard dis- 

 tinctly with an intensity proportional to the size of the opening. In this way 

 different combinations of the fundamental tone with one or more harmonic over- 

 tones, in various degrees of intensity, can be made, and musical tones of varying 

 quality (the vowels) produced, v. Helmholtz made the following vowel-com- 

 binations: U = B, together with faint b and f 1 ; O = subdued B, and strong b 1 

 and weaker b, f 1 , d"; A = b (as fundamental tone), with moderately loud b 1 

 and f 11 , and strong b 11 and d m ; Ae = b as fundamental tone, with b 1 and f 11 , 

 somewhat stronger than for A, d 11 strong, b 11 weaker, d in and f m as strong as 

 possible; E = b as fundamental tone, rather strong, with b 1 moderate, f 1 likewise, 

 and f ni , as 111 flat, and b 111 as strong, as possible; I cannot be produced in this way. 



(3) G. Appunn has constructed a vowel-apparatus of organ-pipes. There are 

 20 open, loud-sounding pipes from the fundamental tone to the 19 succeeding 

 overtones, and 20 stopped, weakly sounding pipes, placed in two rows on a special 

 air-chest. Each pipe can be opened and closed by a valve. A large valve, at 



