Hello! I have 18 years old, and start learn trombone at the 12. Play with a Yamaha Ysl-356g and a yamaha 48 mouthpiece. I'm not sure if this combination works on me , after me , no , but it's only horn I owned , I do not feel well on this mouthpiece,is small,I feel that my lips is moneyless. Usually play 3-3,5 hours on every day.My warm-up is long , 30-60 minutes,even more . I play many exercises, like little buzzing at start 5-10 min , long tones,slurs,scales,articulation,glissandi,chromatic section,intervals,etc,.I like Kopprasch study book and remington flexibility book,and others.I do not know what help me to progress . I'm always looking for new ideas , to help me . I have problems with high range . My range is C# maybe D(hard) (both 2 ) . But G,A,Ab,Bb,B naturally is little strangulated and no have total control on them.I can not articulate good this notes , sometimes Ab on first position crack . My stability on high range is bad . I did not have before this problems ( I say about 1/2 years ago , Everything was fine in the past,or it was not like that advanced ) . Resistance it is also low,I do not succeed to play as long as is wish , it is very frustrating for me,need more stamina . Also , articulation is not very clean and fast . i'm not very good to the chapter technique,never been,is not my strong point,work it for that . I finished school and in this summer I enrol on the music academy ( faculty,like juillard in your country ) . I work hard in every day to become a good player. For this problems what to play to solve them ? I read many good things on forum , you are nice guy with great experience.I do not know if I've given all the details about problem . I think have a fundamental problems on my embouchure or something they are wrong, put too much pressure on mouthpiece ? .
Maybe in the end I will succeed,I would be happy ,until then it's hard
ps : I now , my english is very bad , sorry for that.