Check out this article on Brass Making

[Tubadork]

Seems Pretty cool,
check out Lacquer vs. Un
neat stuff
from an acoustical society:

http://www.acoustics.org/press/133rd/2amu4.html

Bill

[windshieldbug]

I always said this, but you guys said I was crazy!

[Rick Denney]

I always said this, but you guys said I was crazy!

Your sanity is a separate issue, heh, heh.

The study was done on horns, which have a very different acoustic design than do tubas. The bell is large and flat, and damped by the player's hand. The overtones differences between loud and soft playing are much greater with horn, and depend to a much greater extent on the vibration of the brass.

Not much of the differences noted in those charts would apply in the frequencies that are the strongest in tuba sound.

But even anecdotal evidence undermines the notion of a significant effect from the alloy or finish. Some people say a "goldbrass" bell has one effect, and others say it has the opposite effect. Some claim unlacquered is "brighter", and others claim the opposite. It sounds to me as though whatever differences are truly there is more likely to be explained by the normal differences between one instrument and another, likely associated with internal features such as misaligned tubing and solder blobs, and with residual stress from the assembly.

Tests on horns with screw bells have controlled for these effects better than any tests using tubas could, but then we again have the different sound design and frequency band of horns coming into play.

Rick "who thinks the term 'nonlinear' in the article is scientist code for 'unexplainable'" Denney