Marshall,
About which high C are you speaking? The note naming system for treble clef is foggy; If you`re referring to the C above the staff, or 2nd ledger line C, your son is doing FINE! If you are referring to the C within the staff, then he has some issues. I can not help with not being able to play above C in the staff without seeing him (and probably not even then - I`m just a student, too), so if this is the case, get him a good, respected teacher. Not a teacher from a local music store, but a true professional trumpeter. Call a local symphony and ask to be put in contact with their principal trumpeter or something. If you want some help finding a teacher in your area, email me with your city and state and I`ll ask my college professor and some other first-line pros I know.
Now! If you were referring to the C above the staff, congratulate your son. I didn`t have a dependable, workable high C until late my senior year of high school. Rather than think about getting high notes, he should be concentrating on improving everything between low F# and top C. After all, 95% of what us trumpeters will ever play is in this range and it`s vital that we can play fluidly within it.
Ask your son to open up his Arban`s book to page 191 and pick a lyrical etude and work on making it as beautiful as possible. If he doesn`t have an Arban`s book, get him one. Go to a music store and say "I`d like the Arban`s book for trumpet." Also consider picking up any of the method books by Vizzutti, Charlier, Stamp, Concone, W. Smith, Clark, and Schlossberg. These are all standards and are invaluable to trumpeters.
The only way I know of to build a high register is to use it. Play stuff that includes all of his range, but as smoothly and nicely as possible. Musicality will make him great!
Cheers! and contact me if you`ve more questions,
Aaron Norlund
Aaronnorlund@hotmail.com
p.s. - visit www.trumpetherald.com
and
http://www.bachbrass.com/phpBB/