Klarinet Archive - Posting 000327.txt from 2004/06

From: "Keith" <100012.1302@-----.com>
Subj: [kl] RE: Round
Date: Mon, 21 Jun 2004 04:41:31 -0400


Ormond,

I am speaking theoretically, since I have not tried it. But I don't think
there is any acoustic reason why a barrel has to be round. I think that the
vibration modes in the barrel will be dominated by the cross-sectional area
rather than the shape.

It may indicate a badly made barrel. Or if the instrument is antique,
shrinkage over the years from drying out will usually cause the bore to
become oval. This is because the shrinkage contraction is different in
different directions in the wood (radially and tangentially relative to the
original log). If the overall bore has got smaller, then acoustic properties
could be restored by restoring the original cross-sectional area. Carefully
- you only get one chance. I recall Tony Pay speaking on the list of
improving an old instrument by doing something like this, but I don't recall
if it was because the bore was oval or simply too small.

Keith

> ------------------------------
>
> Date: Sun, 20 Jun 2004 21:56:30 -0700
> To: klarinet@-----.org
> From: ormondtoby@-----.net (Ormondtoby Montoya)
> Subject: Round?
> Message-ID: <11700-40D66A7E-1727@-----.net>
>
> To anyone who frequently takes (or has taken) actual careful
> measurements:
>
> I know that opinions differ as to which barrel taper(s) and/or
> diameter(s) are best for a particular instrument & setup. 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?
>
> 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?
>
> Thank you,
> Ormond

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