QUOTE(dacapo @ Jul 4 2009, 10:30 AM)

I've just accompanied a young baritone horn player in his Grade 2 exam. Last autumn when he was only 7 I accompanied his Grade 1 for which he got a distinction, and since then he's enjoyed playing in a local festival. He's playing very confidently and musically, with a noticeable dynamic range, accurate rhythm and articulation. Apparently his teacher (who teaches him at one of the local primary school) does sometimes mention not puffing his cheeks, but he's still doing it all the time and I don't think he's convinced it matters. I sent his Mum (who plays cellos and piano) a link to a picture of Dizzie Gillespie with his bull-frog cheeks but I'm not sure if she showed it to X.
I expect to be playing for him again. Am I right to be concerned? If so, any suggestions for interesting ways to help him to stop? Mum doesn't want to pester or upset X.
When I began learning tenor horn in primary school, Diz was used as an example of what would happen if we puffed our cheeks. To this day, now on trumpet, I'm convinced that Diz was an unusual case. There's a condition whereby someone's skin becomes extremely, abnormally stretchy.
If I puff my cheeks on trumpet, my range decreases by at least a fifth, and everything else goes to pot. I don't think Diz could have played as well and high as he did without firm corners, so I think his cheeks just did that.

His neck went too, which is often not mentioned.
Maybe a low brass specialist will have more to say, but I'm fairly certain some tuba players puff their cheeks at the low end... Maybe it's not that big a deal for a bari player? The air pressure is lower than on higher brass, so any risk that is there may be reduced.