TubeNet

http://www.popsci.com/results?query=tuba" target="_blank" target="_blank

From March 1932

What a great way to solve an problem! I'm sorry this did not catch on, to be honest. Imagine the demand!

That tuba is pretty neat, too!

It would be interesting to see the "back view" of that horn, but I bet it is not much different from the last bend of a Sousaphone (before the bell ring) rotated 180° and the bell inverted - if it was made with two mounting rings it could be reverted to a standard Sousaphone shape in a few seconds!

Somebody with a semi-assembled Sousaphone (not me at this moment) could check my theory pretty quickly. I just tried doing it in Photoshop but that didn't work too well.

I used Google's new patent drawing search to find a "rear view" of this thing - pretty much as I guessed - two screw rings to allow reconfiguration (to a standard-ish Sousaphone shape) and storage.