Topic: Dr. L. Hugh Cooper's thoughts on Vibrato
1."In my considered judgement a normal bassoon vibrato should consist primarily of "horizontal" variations in intensity coupled with a secondary "vertical" pitch fluctuation caused by the periodic changes in pressure.
2. Theoretically, these desired fluctuations can be inserted at any point in the breath support system, by alternately increasing and decreasing the rate of airflow pressure through the appropriate sets of muscles.
3. Possible musculature that might be involved in this process and the feasibility of their use are:
a. Abdominal muscles - (external and internal obliques, tranverse and rectus.)
1. According to Grey's Anatomy, "forced expiratory actions are performed mainly by the flat muscles of the abdomen assisted by the rectus." These muscles are largely involuntary in function and generally con-
sidered by physiologists to be too-massive, difficult to control, and slow to serve as a normal function of a musical vibrato.
2. The strong abdominal muscles ARE the muscles of expiration and as such used to produce what is incorrectly called "diaphramatic support". They also can and are used to produce a slow, heavy pulsation, akin to a vibrato, but more analagous to a Baroque ornamentation called "Begung".
3. Many teachers use abdominal muscles to introduce vibrato to their students, having them pulsate the breath to a metronomic beat. But, at best, this heavy muscular approach never achieves sufficient speed or delicacy for use as a real vibrato, but only serves as a starting catalyst. I prefer to avoid this artificial transitory approach to teaching vibrato.
4. Performers who think they are using a diaphragm vibrato are involving other muscles to produce the effect. (A good example is Chris Weait's brief videoscopic study which clearly pinpoints the actual source of his supposed diaphragm vibrato, as gravitating to his throat area).
Chest, (rib) muscles - (external and internal) oblique intercostals.
1. One set of these breathing muscles serves to raise the chest while the other lowers the rib cage.
2. It would require a rapid alternation between these two sets of rib muscles to produce any semblance of vibrato.
3. Again, such activity would be physiologically problematic at best, and certainly not feasible within the frequency range of an acceptable vibrato.
d. Laryngeal Muscles:
1. These sensitive voluntary muscles control the tension and contour of the vocal folds (cords) and, therefore, determine the size and shape of the glottal opening which lies between the folds.
2 This valve-like apparatus can be consciously controlled to modulate the flow of air from the lungs (trachea) into the vocal tract. Its function, while playing a wind instrument, really represents a form of vocalizing (albeit silently); however, the vocal folds must be slightly more separated to avoid phonation.
3. At this narrowest point in the air column a slight change in vocal fold tension causes the glottal aperture to vary in size, thus regulating the flow of air into the oral cavity.
4. In my opinion the glottal area with its vocal folds represent the most practical, controllable and musically sensitive locus for producing a vibrato.
5. Except for special effects, the bassoon vibrato should be produced naturally like that of a singer." I agree with Dr. Cooper's analysis and have used this strategy in teaching vibrato to many of my students. Sincerely submitted, Gerald Corey