Klarinet Archive - Posting 000705.txt from 1998/09

From: "Kevin Fay (LCA)" <kevinfay@-----.com>
Subj: RE: [kl] Pitch standard confusion
Date: Sun, 20 Sep 1998 07:51:29 -0400

I've heard that the critical element is not the temperature of the horn
(leading to expansion/contraction) but the temperature of the air (which is
affected by the temperature of the instrument and vice versa).

I'm told of a film where some enterprising music students under the tutelage
of one Arnold Jacobs put a tuba in a deep freezer. Once very cold, it
played extremely flat until (quite literally) warmed up.

As far as cracking goes, it's not the temperature of the horn that kills it.
It's the DIFFERENCE in temperature between the bore and the outer surface.
If the bore gets warm (by playing, for example) it will expand--if the
surface is still cold, it will split. Moral: while it is OK to put your
clarinets in the trunk of your car, don't play them until they get back to
room temperature.

kjf

-----Original Message-----
From: Dee Hays [mailto:deerich@-----.net]
Subject: Re: [kl] Pitch standard confusion

-----Original Message-----
From: Roger Garrett <rgarrett@-----.edu>
Date: Saturday, September 19, 1998 10:06 PM
Subject: Re: [kl] Pitch standard confusion

>Your arguement is sound.....thanks for presenting it.
>

Thank you Roger. As a working engineer, one of my areas of expertise does
happen to be thermally induced stress albeit I work with metals rather than
wood but the principles are the same. Thermal effects at first do APPEAR to
fly in the face of logic but once you sit down with the equations and work
through them, the correct premises become clear.

Since people don't get burned at the stake or subjected to the Inquisition
any more when they present new information, I don't get excited when someone
isn't convinced by the evidence. Afterall the world was round even though
"everyone knew it was flat" and the earth orbited the sun when "the earth
was the center of the universe."

My point was that the thermal expansion of the wood itself is so small as to
be unable to noticeably affect the pitch of the instrument so that we must
look elsewhere for thesource of the pitch problem.

Just for the record, if one takes a hoop and heats the inner diameter and
not the outer, the inner diameter still grows outward putting stress into
the hoop since the outer (unheated) diameter restrains this expansion.

Dee Hays
Canton, SD

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