Posted by Rick Denney on April 14, 2003 at 10:54:13:
In Reply to: Re: Re: Re: How to stuff a PT-6 posted by tubagrow on April 14, 2003 at 10:14:38:
I'd like to see some test results showing that lacquer damps any audible overtones on a tuba.
And I'm also not absolutely persuaded that freeing up some upper resonances (even assuming it's possible) will make an instrument sound brighter. Well-tuned upper harmonics can make an instrument sound deeper by establishing a well-ordered series of overtones whose spacing generates the appropriate low difference tone (i.e., the fundamental).
In my own tests, the levels of the resonances in the ringing-brass range were so far below the bottom 8 or 9 overtones that they aren't hearable. And both horns I tested are unlacquered brass. And when I knock on a bell with my knuckle to hear the brass ring, I can't hear any difference in the resulting clang regardless of the status of the finish.
Any mechanical brass resonance in the lower frequency ranges that could hope to affect the sound are well below the damping capability of a thin layer of lacquer.
I believe the test is nearly impossible to conduct, unless a mechanical transducer is used. You'd have to filter out sample variations to test horns side-by-side, or you'd have to control for differences in the player if using the same horn with and without lacquer. And most folks who have the lacquer removed are doing it along with other repairs, and the effects they notice may well be caused by those other repairs even if it isn't a change in their own playing or perceptions.
I'd be more prepared to believe that trumpets could experience some subtle effects, but their frequency response range is four times that of a tuba.
I've linked my article on the subject, which needs some corrections and updates, but the frequency response measurements are accurate.
Rick "not buying it" Denney