My HD does not kid when it comes to this. All euphonium players must read BC to be in high school band. We had a kid who started on trumpet in 5th grade, then switched to euphonium in 6th and took off like a rocket. He continued to read TC and made 1st chair all region in 7th and 8th grade. When he got to HS we was placed in our lowest band (HD's exact quote) "until he learned how to be a real euphonium player treble clef wanna be." Kid quit.