I am a college senior and am having some chop issues. After about an hour or two of playing my upper register gets very fuzzy and i start to have a double buzz. This occurs above high B (I can only play to a puny high G at best). I have experienced trouble before because over the summers i do drum corps. As i am preparing for a senior recital, i was wondering what i can do to still practice regularly and mend this problem. To get rid of it last time, I had to take six weeks off the horn, which i can't do. If it matters, I am currently playing on a xeno with a 1c mouthpiece. Switching to a smaller mouthpiece does not help the double buzz or fuzz (have tried 1 1/2c, 1 1/4 c, 3c, Zeus E3, and a Marcinkiewicz M8). Any help on this problem would be appreciated.