I used to able to play high notes (D-F) really well. Back in late May, for some reason, I started to not be able to go that high. It`s realy strange and frustrating; its almost like it happened over night. Its starting to get better but not where I would like it to be. Does any one know a possible casue to this and any tips to play high notes? Thanks!

Start in 7th posistion E and slur up, and so on and so on. Thats how I got my high notes going.

Hello, I have the same problem in the high notes. I think that I started to think to much in my embrochoure, and I forgot a little my concentration in the air.
I start to have some results when I do some exercises in low notes(long notes in pedal notes), and after I try to go up.
I f you have more Ideas how to combat this please contact me for this email: vieiratrombon@hotmail.com
Thank you.

The problem with losing high notes is not that you are losing something, but that you are gaining something else. This usually occurs as you begin to center the mouthpiece and play into the center of the horn instead of just making the right note come out. When you learn to open your sound up and actually make the horn resonate, you lose a great deal of facial pressure and tension. This gives a much better sound, but you can`t go as high. Practice doing lip slurs and slowly over time, you will get your range back. The difference is, now it will sound much better and be more reliable. Good luck.