raw brass

[windshieldbug]

A lessening of about 5% in the high frequencies that were produced, after the lacquering

Thanks MA, maybe I wasn't crazy after all. Now as to if you could hear the difference out in the hall...

[Joe Baker]

The best possible test would be to use a dinner bell being struck by a mechanical striker. The same bell could then be laquered and then silver plated to show any differences. Rick Denney, where are you when we need you?

I did the dinner bell test with a small brass bell and the sound was audibly deadened by the laquer. I used Testors brand clear coat and only spraved the outside of the bell, not the dinger. I don't think the conclusion is completely applicable in the case of a tuba because a tuba has lead solder in it and the bell is a percussion instrument.

Yeah, I think there are a lot of reasons why this isn't really a meaningful test.

First (as you have suggested), the sound produced by a tuba is only secondarily a function of the material; in other words, the tuba doesn't CREATE the sound wave, it merely impedes some frequencies and reinforces others.

Second, the teensy bell produces only high frequencies, which are present and even significant in the tuba sound, but are not the PRIMARY sound. Minor attenuation of high frequencies, if it DOES happen when putting sound through the bell (as opposed to making the sound by striking the bell) would have only a very slight effect on the tuba sound. If my memory serves me correctly, Rick Denny's tests have indicated that a partial that is more or less missing DOES affect the sound, but slight attenuation doesn't measurably affect it.

To illustrate how potentially flawed the exercise really is, compare the sounds of playing a brass sousaphone and a fiberglass one, and the sounds or ringing a brass and fiberglass bell. I don't think it's likely you'll be able to find a fiberglass dinner bell (anybody want to undertake the project?), but you CAN rap brass and fiberglass tuba bells with your knuckle and hear the difference. They may play a bit differently, but the difference when struck is MUCH greater. The effect of materials, then, on an object's ability to resonate sound is not as great as it is on that object's ability to generate a sound when struck.
______________________________
Joe Baker, who is still looking for an applicable side-by-side double blind test.

[tubarepair]

I'm still finding it hard to believe that someone tried the dinner bell test . I guess the emoticons don't really work

DLH