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CONCEPTS OF PHONATION |
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build normal breathing reflexes into tone-supporting techniques of breathing. [577, p. 310]
Pitch regulating factors. The consensus of 39 statements on this subject is that the fundamental pitch of the singing voice depends upon the frequency or rapidity of the opening and closing of the glottal aperture during phonation. [E.g., Negus op. cit., p. 346] It is also commonly held that the frequency (pitch) range of any given voice is influenced by the length, thickness and density of the vocal cords. Mackenzie claims (from laryngo-scopic observations of 300 to 400 singers) that only a portion of the glottal edge is in vibration for low tones and that as the vocal pitch ascends to the falsetto quality (see Chapter VI), the vibrating segment travels toward the anterior end of the vocal lips. [364, p. 67] This observation, made with the naked eye, is later confirmed by Farnsworth, who used high speed motion picture photography to study vocal cord action. [168] Negus* explanation of the falsetto mechanism is also interesting: In falsetto (head register) the cords remain blown apart and are outwardly bowed by the breath stream. "Only a part of the margins of the glottis are in vibration. . . . The mechanism appears to depend on contraction of the internal fibres only of the thyro-arytenoid muscles, associated with considerable variations of tracheal air pressure." [418, p. 440]
Farnsworth reports that the duration of each glottal contact of the vocal cords during phonation decreases as the pitch rises "until, in the falsetto, complete contact is usually not attained at all." [Op. cit.] According to Curry, the method of pitch adjustment of the larynx changes as the tones ascend the musical scale because one regulatory mechanism is un-suited to make both the coarse and fine adjustments necessary to cover the entire range of the vocal gamut. [124, p. 66] In lower pitches the cords are relatively thick; in higher pitches they are "thinned and stretched." [Bartholomew 39, p. 122; Kwartin 325, p. 32]
There is however no certainty as to the exact physiological method of tuning or stretching the vocal cords during pitch changes in singing. The various actions compositely described below present typical conflicting viewpoints, incompletely picturing the entire process of pitch adjustment:
1. The palate-to-pharynx muscles (rear pillars of the throat) "aid the smaller laryngeal muscles to stretch the cords" for higher pitches. [Bartholomew 39, p. 130]
2. The vocal cords are stretched by the tipping of the cricoid (sic) cartilage. [Jones 307, p. 10] |
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