[quote=@LetMeDoStuff]
<Snipped quote by Obscene Symphony>

French Horn is considered the hardest acoustic instrument, as it has a longer tube length than most other instruments and a really right mouth-piece, making lip muscle be dependent. I'm not bragging, I'm only Grade 5 and I've been on it for 7 Years XD
[/quote]

As someone who plays all the brass instruments professionally, I can safely say that the horn is the hardest of the bunch (with piccolo trumpet being a close second). But in terms of projection/volume two trumpet players can cause some serious trouble for a horn player. xD

All that said, one bass trombone can bury an entire brass section pretty easily. :D