I've been asked to play the organ with a brass ensemble at a gig soon. The thing is, I am not sure the organ is at concert pitch - the question is therefore, how "tunable" are brass instruments in general to deal with this kind of eventuality?

Thanks!

You're in trouble if the organ is too sharp, and particularly if it's cold, as you won't get the brass up to your pitch. Down here in Devon we have 'Hele Pitch', named after the organ builder, which is about a quarter tone sharp. As I do quite a few weddings, I actually cut about a quarter of an inch of the tuning pipe of my piccolo trumpet so that I could tune up to the organs round here. But un-modified instruments will always struggle.

Just keep fingers crossed it's at concert pitch!!

Brian