I have been playing for 8 years and im 17, about 6 months ago my chops were able to play easily over high C and with good tone. But for the last couple months notes above the staff have sounded terrible. they are airy and scratchy and i don`t know what the problem is... My tone in the staff is perfect but once i go above...it isn`t good.
Could it be my lips are tired out? should i take a break for a while or does it have to do with jaw position or anything? i think my jaw is fine. I am first trumpet at my school so its kind of a big problem.

thanks

and nothing has changed? YOu havn`t changed mouth peices or anything? Have you cleaned your mouthpeice recently? Ran a snake through your horn? If the pad on your spit valve have gone bad air can leak out and cause that. Try borrowing someone else`s horn long enough to find out.

Once you`ve put a check mark next to all those, take a day or two off, and then think about trying a mouthpeice with a deeper cup.

I accually did switch mouthpieces a couple months ago. from a Bach 1 1/2C to a Curry 1C. the Curry is deeper and i have a better sound. so is it just the deeper cup that is my problem in the upper register? Because i have been playing on it for a long time now and i would think i should beplaying higher with better tone.

When in doubt go back to basics. Why go to a new mouthpiece when it worked well 6 months ago? Try buzzing w/o the mouthpiece and about 20 minutes of very soft (ppp) and easy (No or little pressure) long tones on the staff. Be conscious of arm pressure;let your chops do the work. It`s important to be physically conscious of what your chops are doing while playing these long tones. You should be able to feel the air go through the aperature. Focus on that as it happens. Long tones can be boring but it`s like working out in the gym...if you want to have the results you need the discipline. Good Luck