I'm working on a jazz festival audition. This is my 7th year playing. I'm having trouble playing a high E in a piece, and I cannot get it. I'm playing low tones and trying to work up to the note, but I seem to have reached my limit. The D is not very difficult to get, and I can play a good high C without even warming up. Is it possible that I have reached my limit? What can I do to expand my range?