Klarinet Archive - Posting 000697.txt from 1998/09

From: Bill Hausmann <bhausman@-----.com>
Subj: Re: [kl] Pitch standard confusion
Date: Sat, 19 Sep 1998 22:21:03 -0400

At 03:22 PM 9/19/98 -0500, Dee Hays wrote:
>The circumferential change is still proportional and on wood is very much
>less than the 0.07% that I calculated for aluminum. For a 1/2 inch diameter
>that is less than 0.00035 inches in aluminum. Again wood is even less.
>Thus diametrical or circumferential changes in dimensions due to thermal
>expansion are NOT enough to change the pitch of the instrument and the
>controlling phenomenon is the sound wave moving out of the horn into the air
>with the different density.
>
>By the way a hoop expands on both the inside diameter and outside diameter
>when heated so the bore gets larger when warmer not smaller. Remember that
>to loosen a metal cap on a jar, you run hot water over the cap. If the
>inside diameter got smaller, the cap would get tighter not looser.
>
I think the jar thing works because a) the lid material is very thin,
negating the difference between inner and outer diameter and b) the lid
expands more rapidly than the jar mouth. But that notwithstanding, I'm
still not convinced. A hot clarinet in a cold room will still play sharp
until it cools down completely, even when the AIR inside of it is fully
warmed. Whether it is because the bore expands or contracts, the
temperature of the INSTRUMENT would seem to be the critical factor.

Bill Hausmann bhausman@-----.com
451 Old Orchard Drive http://www.concentric.net/~bhausman
Essexville, MI 48732 http://members.wbs.net/homepages/z/o/o/zoot14.html
ICQ UIN 4862265

If you have to mic a saxophone, the rest of the band is too loud.

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