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I've been talking with a trumpet player about forming a quartet or quintet to play for recreation and a few times a year at church services. IDK who I will be able to scare up besides the 1st trumpet...there is a euphonium player who is a church memeber, if he wants to play with us, but IDK yet. So my question is: what other instruments might be used for the inner voices? Would a euph play the trombone part, a horn part or the second trumpet, or any of those? Any thoughts?

royjohn, 75 y/o tuba newbie

For years we played 2 x cornets, 1 x horn, 1 x euph, 1 x tuba.
https://youtu.be/qK2Bbr9O-8I

Several years ago I was part of a brass quintet in San Diego and we couldn't find a french horn player. I transposed the parts for euphonium. I love French horn but I thought it was a great sound with the euphonium.