I play a Prestige and have problems with Ab(concert) above staff. I have a decent high range (Eb) and can get them all with good sound and pitch. The Ab, however is my only problem - either can't hit it, or if by chance I do is fuzzy and out of tune. I've tried different combinations of mp and euph brands - with same results. I have a physical and/or mental problem with that note I can't figure out. Any advice will be MOST appreciated.