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TRAINING THE SINGING VOICE |
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3. "Rotation outwards of the arytenoid cartilages tenses the edges of
the glottal bands [cords] and at the same time prevents closure of the glottis." [Gametti-Forbes 198, p. 86]
4. The rate of vibration depends upon the tension, length and shape of the cords as well as upon the pressure of the air stream. [Passe 443, p. 56]
5. Two opposing sets of muscles operate to tense the vocal cords. These are the arytenoid and the crico-thyroid muscles. [Stanley 578]
6. Fitch changes are determined "by the degree of [internal] contraction of the thyroarytenoid muscles" and not by the external stretching of these muscles. [Negus 418, p. 439]
Russell's X-ray studies of the larynx in action submit no evidence that a raising of the pitch is accomplished by the stretching of the vocal cords. Therefore, Russell feels justified in claiming that "our concepts on even this fundamental subject will have to be changed." [479] Redfield's summary of pitch control is purely theoretical but acoustically interesting: "There are three possible means by which the pitch of the human voice could conceivably be controlled either entirely or in part: 1) by varying the tension of the vocal cords, 2) by varying the capacity of the resonating air cavities, or 3) by varying the size of the orifices by which the tone pulsation is permitted to escape from the resonating air cavities to the outer atmosphere." [462, p. 272]
Evetts and Worthington, Stanley, and Clippinger submit the possibility of using breath pressure as a pitch controlling factor. In this connection these authors claim that a fitful increase of breath pressure during phona-tion is frequently the cause of singing off key. This is explained by the fact that increasing air pressure tends to stretch the vocal membranes (cords) and heighten the pitch of a given fixed tone. As the pressure expends itself, the correct pitch is restored. [Evetts and Worthington 167, p. 81; Stanley 578] Unconsciously applying this principle, singers often try to reach high pitches by sheer force of breath, while holding to a constant adjustment of the vocal cords. When high tones present difficulties, "it is because they are produced with too thick a string, that is, with too much resistance of the vocal cords." [Clippinger 104, p. 32] Evetts and Worthington also point out that the pitch range of the average male voice lies "about an octave lower" than the average female voice because the lengths of the vocal cords of each sex have a ratio of 15 to 11. [167, p. 24] There h no comparable difference in length, however, between the vocal cords of a bass voice and a tenor. [White 658, p. 61] (See also Chapter VI) |
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