When one has an embouchure problem, is it best fixed by sound alone? That is, will sound focus alone cure the problem? Or, is it best fixed by analytical adjustment? Some contend absolutely one way; some contend absolutely the other. And, to be totally honest, some just contend, generating more heat than light.
The answer, it seems to me, lies in the player's make-up. The way that the player receives and responds to information should determine the approach that a teacher or advisor would take in helping.
Attempting a "fix" by oneself seems to me to be perilous, perhaps even for the seasoned vet, certainly for the aspiring professional, and absolutely for the novice. As a professional who has had success as a player and a teacher, if I had a problem that I believed was embouchure-driven, I would seek the most competent help I could get.
I have had many students who, among other things, have had embouchure problems. By problems, I mean lip and muscle functions, and placement issues that the vast majority of professional teachers recognize to be problematic. They include excessive smiling, the peachpit chin, the lips rolled out, playing too far in the red and others. Usually, I have found that some technical advice, plus a rigorous listening and observing regimen, combined with a player's willingness to step back and address the problem are the keys to success. How the player responds to the sollutions proffered determines which I emphasize more.
By a large measure, the player's reticence to step back, do less (especially in terms of range) and get the problem fixed, has been the chief obstacle I have seen in fixing embouchure problems. However, once the decision has been made and the commitment has been grounded, I have found some technical information to be invaluable.
As I have contended in this forum before, there is not one correct way to play the trumpet, but there certainly are ways that are almost always wrong. With the exception of some very young students, every student I have advised in this regard has believed that s/he was the exception. I then applied these tests (actually, I had applied them in my listening previously; now I let the player apply them.)
1) Can you play with a characteristic sound in all registers?
2) Can you play in tune and can you adjust when you hear that it is necessary?
3) Is your high register commensurate with your stage of overall musical development?
4) Can you play an entire rehearsal or concert without reaching embouchure failure?
No player whom I recommended consider a change could answer these questions affirmatively.
The vast majority of competent professionals will agree that how the
player sounds is the most important issue. The question then follows, what
is the optimum way to achieve that sound? I have seldom found that sound
alone is sufficient to correct well-ingrained habits. (We are usually dealing
with these when embouchure changes are needed.) I usually recommend exercises
on the mouthpiece alone in these instances. The player makes no moral judgement
on how s/he sounds when buzzing the mouthpiece. After all, who expects
the mouthpiece to sound like a trumpet? Playing the mouthpiece alone allows
the player to experiment without the self-deprication that almost always
from attempting such fixes on the trumpet. (I had one student about whom a former colleague mused "every morning I practice, and every
morning I learn a new word.)
By focusing on getting the physical obstacles out of the way, the air flows more freely, the buzz is more full, and the sound can be created with more ease.
I should add that I do my best teaching with my horn in my hand. I play a lot for my students. Nobody can change his/her sound until the sound in his/her head changes. But I have found it extremely beneficial to couple sound demonstration with simple technical instructions in fixing embouchure-related anomalies. Most of the best teachers I have known have done likewise.