Klarinet Archive - Posting 000334.txt from 2004/06

From: GrabnerWG@-----.com
Subj: [kl] Concentricity of barrel bore to upper joint bore; was: Round?
Date: Mon, 21 Jun 2004 13:32:05 -0400

Ormondtoby ask (regarding barrel bores):

<< But, is it true that everyone agrees that 'as-close-as-possible' to perfect
roundness (perpendicular to instrument axis) is always best, regardless
of the instrument & setup?>>

The meaning of the term "perfect roundness" eludes me. I believe that you are
asking if the bore of a barrel must be concentric with the bore of the upper
joint of the clarinet.

Logic would lead us believe so.

In fact, if you inspect/measure many professional level clarinets, as I have,
you will see that many of them have a barrel where the barrel bore is not
concentric with the bore of the upper joint. (Sometimes this is not the fault of
the barrel, but the fact that the tenon on the upper joint was not machined
correctly.)

In actual practice, this seems to make little difference. I have seen
situations where the bores are concentric resulting in only an average setup, and I
have seen situations where the bores are NOT concentric resulting in a good
sounding, well tuned setup.

<<If so, then when you measure the bore of a professional quality barrel
that has seen significant use, how far 'out of round' would it need to
be before you raised your eyebrows and told the owner: "You need to do
something about this"? 0.01 mm? 0.1 mm? 0.2 mm?>>

Only going by the numbers is fraught with risk, simply because there are too
many interrelated variables.

I tell an owner "that they need to do something" when a barrel produces
outsized, or undersized 12ths in the upper joint. You must be careful here, as
different mouthpiece bores can magnify or reduce tuning anomalies. See Benade on
tuning effects of the barrel and mouthpiece bore combination. If you don't have
the owner's mouthpiece, you are not seeing the real picture.

For best results, to tune the instrument, you need the instrument, the
barrel, the mouthpiece, and often -- the person. There are far too many interrelated
variables.

Walter Grabner
http://www.clarinetxpress.com/
World-class clarinet mouthpieces

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