Is there a "correct" embouchure? I've paid attention to my technique in regards to not tensing, relaxing my tongue, and using the lips more. However, I've noticed that I can form three different embouchures: one feels like a "happy" face, another neutral, and the final like a "sad" face. Which should I use? (They probably don't look different, but they feel that way.) I'm not very sure which I'm using, because I don't feel much effort until near the end of 3 hours of marching band practice (we do 1-2 run-throughs at the end). I am playing with a relaxed tongue, with my lips working, but I don't "feel the burn" until we're doing run-throughs.