well you're most likely having problems with at least one of two things if not both that have to do with high notes. One is that the notes are just out of your range and the other is that you are just getting tired after the first four measures. I know of exercises to help develop your high range and your endurance. but you need to make sure that you are using allot of focused, energized air. and you are rounding your top lip while tightening and not pressing your lips together. high notes are easier than you think. be patent.

to expand your range start at a top space Bb and then go up in SLOW, STEADY half notes while breathing for four beats in between. in a pattern like this"Bb,C,Bb,breath,C,D,C,breath,D,Eb,D..."staying in the key of Bb. You simply go as high as you can. make sure you're breathing and keeping it steady.

to improve your endurance there are many things to do. I do allot of high lip slurs. I also do high lip work with just a mouth piece. for example I start at a low Bb and I slur up in different patterns two octaves to the high Bb I then slur from there to the c and then the d(all in first)and I just stay right there going B,C,D,C,B,C,D,C...you can do that in any position. try going to the high F in 6th position and doing the same thing (F,G,A,G,F,G,A,G) all in 6th

A high range/endurance exercise thats helped me is the going up by half steps...and I've heard (haven't really worked on) doing a giant gliss from say a E in 7th to the really flat/sharp (my mind just slipped me) in 1st, go out again to 7th and slowly do it again. Repeat this.

(I haven't read through the other post yet, so I'm going to throw this out anyways)

A thing to remember is, as many players have said, its not the amount of practice, or how intense of practice you do...its all about the effectiveness of the practice. If your stressing your high chops trying to build them too quickly and not giving yourself enough rest, you'll just hurt yourself a lot more than you will if you pace yourself. So make it whenever your working on this an effective one, and not a try to get this in 1 night type of deal. It will take time.

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Also another exercise I've done as well, is the lip slurs. Those help me more than anything (especially with braces and lip protectors in). But starting out on say a D to a Bb in first above the bass clef, than working your way up. You should ALWAYS use a metronome in ever exercise you do, especially these; they help with lip trills (if you can't already aren't able to do 'em yet). But take it until you start to feel some pain and relax, blow through some pedal notes nice, soft and slowly, than take a couple minute break, enough to get a drink or something. Than try it again 1 click up on the metronome, and repeat this. But don't think your doing to be able to do it in 1 day again...that'll probably hurt you...but eventually you'll start see a large improvement in your high range, lip slurs, and clarity when switching partials even when moving the slide.
Try to incorporate ways in which you can improve more than 1 thing at a time (like in this case, but not to hurt yourself!!!)

Here's an exercise that has really helped me, it's good for developping high range and endurance.

http://www.sibeliusmusic.com/cgi-bin/show_score.pl?scoreid=34995

Also check up his other exercises for tenor and bass trombone and tuba (just click on his name to go to his page on Sibelius Music).


Another exercise that helps me develop high range, or at least the air aspect of playing in the high register (actually helps finding the right amount of air to blow and the right speed at which you blow it), was taught to me by the private teacher who helped me preparing for my college auditions.

It consists of playing one octave major scales without tonguing. You breath-attack every note, so there is no articulation, you only play with air (of course you place your tongue in the right position to go up in the scales, but you never use it to articulate). You start on a low Bb major scale, one octave, in eight notes at a moderate tempo. Then you play the B natural scale the same way, then C major, etc. You just keep going up chromatically. It'll start getting hard when you reach high C's and above. It might not be good to use only this exercise for high range, but adding it to your daily routine can help for sure.

Talking about daily routines, here's the one I use (not exactly, but I created my own based on this one). It includes yet another high range building exercise which is also good I think. That routine is from Dr. Tom Gibson.

http://www.music.gsu.edu/facsturesources/brassdept/trombonelessonsCD/html%20pages/GettingStarted.html

See also his educationnal website, there are plenty of very useful tips and articles in there.

http://www.trombonelessons.com


That's pretty much it, hope it helps.

"no articulation, you only play with air (of course you place your tongue in the right position to go up in the scales, but you never use it to articulate)"

thats also a good thing to do just in the music period, I do it to get my arm/brain/note in the correct place, I still don't get why it works, but it does like a charm!

Lol yeah it's a good little exercise that one wouldn't necessary think of, but it's very useful. It sounds absolutely awful for anyone hearing you haha but it does work.