When tenors attempt to learn to sing with a low larynx they often make the mistake of associating the movement of the larynx to other parts of the vocal tract – particularly the tongue, the jaw, and the soft palate.
This happens often because of the invitation to sing “sullo sbadiglio” or in a “yawn” position.
At times, tenors are told that if they pull the soft palate very high, the larynx will descend, and this automatically connects opening of the jaw and elevation of the soft palate (and often excessive lateral stretching of the throat) with the descending larynx.
More along these lines, tenors are often told to open the jaw so as to have an unhinged mandible, and that this “yawn” position will lower the larynx.
What is the problem with all these postures? The problem is that you learn to associate physical efforts that do not need to be associated at all costs.
Lowering the larynx is principally about energetic inhalation expanding the bottom ribs. When this is accomplished it takes very little effort to keep the larynx low. One does not need to push the tongue down on the larynx, or open the jaw to cause the larynx to descend.
I invite you to take a look at a video of Richard Tucker singing high notes. What does he do? Take a look at this at 2.14. Did you see how he closes the jaw? What if he associated lowering the larynx with opening the jaw? Then he would not have been able to do what he did.
You have to be able to open or close the jaw independently of the larynx. You have to be able to move the tongue further forward into the mouth on the higher pitches. You can even look at a low tongue singer like Corelli and see what happens to his tongue on his high note at 3.20. By the way, this is a fine example of Corelli singing with a perfectly balanced laryngeal voice, all beautifully and crisply phonated in the same resonant closure of his EE vowel.
Independent movements also relates to the independence between laryngeal movement, jaw opening, tongue movement, and the closure of the cords. One of the main reasons people sing loose is because when they open the mouth to go to an open vowel they also loosen the cords to create a darker sound. Why should the AH be less bright than the EE? Why would the chords be closed on an EE and then open on an OH? If you sing an EE in middle voice, with forward lips and relatively closed jaw, and then you open the jaw to go toward an OH but try to keep the cords closed you will see that doing so modifies the OH (at least this sensation is more evident for those who are not used to singing this way). There is a balance of course, in all things. The closure of the chords should be regulated by the sound and by a sense of flow, avoiding pressurization (air against closed chords). However, initially, it is likely that you will err on the side of compression.
You shouldn’t lose chord closure with movements of the tongue and jaw to create vowels. The efficiency of the sound should remain a constant. This is the foundation of a resonant legato line. If every time you sing a phrase every vowel has a different “impostazione” (vocal set up), then your legato line is ruined. The rich vibrant resonance should flow continuously, which requires that you know how to keep the chords closed independent of jaw, tongue, and laryngeal position.