My "day job" for 50 years has been as a stage director and chair/dean of several theatre programs. The Alexander technique has been an essential part of actor training in all my programs (and many others). We use also in teacher training workshops, because of the strain classroom teachers put of their voices.
There's another thread here where people talk about a "Viennese" bass hold, which I have vaguely adopted. I should add that I made that adjustment with the help of my Alexander teacher - I am centered, neck and head loose, chest open, arms flowing freely from the back; and the bass - despite the odd angle is actually centered in relation to my chest, with more or less equal weight distribution -- and legs open, feet planted (left one on a yoga block).
Definitely recommend it (and --- just a small correction above - Alexander was, I think, an Australian actor)
https://www.amazon.com/Indirect-Pro...p-0195388593/dp/0195388593/ref=dp_ob_title_bk