jimmy

I'm not an acoustic engineer (though this makes me wish I was. . .)
To my knowledge, the mouthpiece is the real instrument. Then, the length of the tubing and its diamete determines the range, and the flare and bell increase volume.

I intend to build a cheap, prototypical, low pitched, LOUD brass thing to make some noise at some football games. So I plan on getting brass tubing, some sort of funnel, etc. to make this goofy looking contraption. However, I was wondering something.

If you were to put an adapter on the end of the tubing that would allow you to hook up another bell, would this make it louder? Is it similar to hooking up another speaker to an amplifier? Or am I just completely daft?
I presume it's the latter.

Thanks for any and all help guys!