I have been having a fun time with a new (to me) tuba - and an interesting comparison with my old one. Very far from scientific, there are a boatload of reasons why these two tubas could turn out different, but their dimensions are somewhat similar - same piston valve bore, roughly same size about a yard from the large end - but not nearly the same weight.Stryk wrote: Sun Dec 13, 2020 1:21 pm So, you are saying research says thicker brass in horns is better than thinner? You DON'T want the horn to vibrate?
The old one - the heavy one - is very noticeably more powerful in the low frequency partials, the floor shaking stuff.
I have in the past experienced feelings of skepticism when I read about miraculous improvements from adding a brace here and there, even if it comes out of one of the finest of tuba workshops, but I've seen the light on that. Brass weight could easily be a similar principle, if it stabilizes the tuba body in a way that prevents any damping.
As bloke mentioned at the top, a tuba is in this respect quite unlike a violin. The violin creates a really audible sound by vibrating its soundboard, so the acoustical properties of the soundboard material are critical to the result. Vibration in the tuba material doesn't create the sound - but it can harm it. I'm not saying weight can reliably improve the low frequency output, just that it could conceivably play a role.
The perfect experiment: pour concrete around a tuba, let it dry, and see how it sounds. I bet it would sound fine. Sort of tricky work, if you want everything to still work (valves, water keys) and no concrete inside it.

very nice sound, crystal clear, so to speak.