Well, today I was supposed to have a great practice but, my lips don't have the same tight seal as they did yesterday! I'm not using pressure, and I am doing free buzzing, and the pencil excercise! I don't whether it's because I'm having a bad day, or I don't really know! It's like yesterday was the best practice and today I barely can hit my high registers! Could it be because of the stress I have from an upcoming event? I noticed that sometimes when I do try to hit higher notes, I lose my lip seal and sometimes I can hear the buzzing sound from the side of my lips. I just changed mouthpieces, could that be it? I went from a 7c to a pretty much to a 7 with a deeper cup, Idk the equivalent or what size it would be. I've never had this problem before, the mouthpiece I switched to has the same cup rim, cup size (In diameter), the only difference is the cup depth. I have been playing for about 2 weeks now with my new mouthpiece and I really don't think its because of the mouthpiece because those 2 weeks were some of the best weeks of my playing abilities of my life. (If that makes any sense). Anyone know any exercises to build a better seal for your embrouchures. I tried everything from whole tones, to my normal daily routine! I just cannot get my high register today. Anyone else had this problem? Maybe I'm having a bad day, I don't really know.