The three places singers hold
The jaw. Tension here is nearly universal and it directly affects the throat, the tongue and the sound. Most singers only notice it when it becomes painful.
The neck. Particularly the muscles at the front and the strap muscles. A neck that braces restricts the larynx and changes the sound, usually in ways the singer attributes to technique.
The breath. A rib cage that does not move freely and a diaphragm working against a held belly. This is where most of the power limitation actually lives.
Why instruction alone often fails
“Relax your jaw” is an instruction to produce an outcome. If the singer cannot feel the holding, there is nothing to release, and trying to relax usually produces a different, more deliberate kind of tension. The Feldenkrais approach is to make the holding perceptible first — through contrast, small movement and attention — after which releasing it is straightforward.
What a lesson might do
Explore how your jaw moves when your tongue is still; how your neck organises when your eyes look somewhere; how your ribs expand when you are lying down; how your pelvis participates in breathing. None of it is singing. Singers frequently find their voice changes noticeably afterwards, often describing more ease in the upper range or less effort at volume.
What singers report
More available range without pushing, less fatigue in long rehearsals, reduced neck and jaw tension, easier breath management, and — often — a change in the quality of the sound that other people comment on before the singer notices it.
Working with your teacher
This is not a substitute for vocal instruction, and a good singing teacher will not feel threatened by it. The pattern that works: lessons address the underlying organisation, then the singing teacher integrates it. Tell both what the other is doing.