Klarinet Archive - Posting 000637.txt from 2004/07

From: ormondtoby@-----.net (Ormondtoby Montoya)
Subj: Re: [kl] Material influence on sound...one more time
Date: Sat, 17 Jul 2004 00:21:55 -0400

Lars wrote:

> For a material to affect the resulting sound, it
> MUST vibrate sympathetically with the vibrating
> column of air.

This isn't quite true, Lars. Materials can _absorb_ energy without
vibrating to a measurable degree themselves. Especially in the case
where the absorbing material is massive in comparison to the energy
supplied, it is reasonable to wonder whether the body of an instrument
can absorb energy and hence affect the air column vibration without the
instrument itself vibrating to a detectable degree.

That is, the discrepancy between the air column's low energy and the
instrument's comparatively huge mass can *contribute* to hiding what's
really going on.

Also, even if the clarinet itself doesn't vibrate to a measurable
degree, perhaps the degree to which it reflects vs. absorbs energy can
have a measurable effect on the air column's vibration.

Some day, when I have built two barrels that are as close to identical
as possible, and both of them have a drastically larger outside
diameters than a barrel is supposed to be, I intend to cut one of them
down to considerably undersized and then listen to the pair of them. I
may even try to find someone who will graph their acoustic spectra for
me (when played by someone with a more stable technique than I have)
before I cut one of them down.

Morrie Backun or Walter Grabner or Clark Fobes all have the boring
equipment to try this. I know that at least one of them has CNC
equipment and can probably do this experiment more precisely than I can
with my kluged-together-on-the-cheap equipment. I've often wondered
why one of them hasn't done so and announced the results.

It's not clear to me whether such an experiment would be most revealing
when playing only mouthpiece+barrel vs. with the entire instrument, or
perhaps boring a pair of unadorned (no tone holes) tubes and attaching
them, one at a time, to the same mouthpiece or to a whistle's fipple.

....but the bottom line (imo) is that measuring how the instrument's
body does or doesn't vibrate does *not* tell the whole story, and this
is the major loophole in Benade's measurements.

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