TubeNet

Hi TubeNet!

I'm a bass player learning to play the tuba, so forgive me if this answer her is obvious to any real brass player, but I have an old King Bb bell-front tuba...I'm wondering if there's a reason why I shouldn't practice with the bell unattached. I'm guessing it changes the pitch if I do that, right? Thanks for the help!

You are correct, tone and pitch will suffer immensely.

It will more or less play in B, the intonation will be marginal, and the tone will be terrible. You can do it, but it will be sort of like anti-practice: you will be worse than when you started. And you would have to change your name to BellOffGuy.