Weekly Teaching Tip – April 4, 2018
by Tricia Grey’
2. The coordinated balance of TA/CT muscle activity: Pitch is created by alterations in the length, thickness, and tension of the vocal folds. This is controlled by the coordination of the TA and CT muscles, responsible for shortening and lengthening the vocal folds. These muscles must be coordinated to work together cooperatively in order to sing from low to high without straining or cracking. In the chest voice or lower register the TA muscles are more active and the vocal folds are shorter and thicker as the TA muscles contract the vocal folds; as the TA muscles contract, the vocal folds, comprised of the TA and vocalis muscles along with a small layer of mucosa and ligament shorten and push toward one another.
In order to sing higher, the CT muscles become progressively more active, tilting the thyroid cartilage forward so the vocal folds are stretched and lengthened, while the TA muscles gradually reduce activity. Both muscle groups are active in the lower register — the CT muscles work against the contraction of the TA to raise pitch. As you sing higher, however, the CT muscles take over more and more of the work until, on the highest pitches, the TA muscle is largely quiescent. This handoff requires a smooth coordinating of both muscle and resonance or a flip or vocal break will occur.
This coordination is something that needs to be developed — few singers are gifted with a naturally balanced voice. Usually singers who prefer the sound of the chest voice try to push that coordination upward, creating strain and vocal abuse. Others who prefer the trained classical sound often bring the lengthened vocal folds and formant/harmonic balance of the upper register too low, creating a breathy, weak tone in the lower register because, without the correct formant tuning the vocal folds are unable to maintain compression and appropriate adduction.