Klarinet Archive - Posting 000475.txt from 1996/05

From: niethamer@-----.EDU
Subj: Re: Register key tube
Date: Mon, 20 May 1996 23:18:11 -0400

> On Sun, 19 May 1996, Cynthia K Harris wrote:
> >
> > > Does anyone
> > > know why the register key tube needs to jut into the bore.
> > >
>
On Mon, 20 May 1996, Josias Associates wrote:
>
> There was an interesting thread on the subject of subharmonics on
> the list perhaps about a year ago. My personal interest resulted from my
> A clarinet occasionally producing subharmonics -- something like a brief
> buzz -- just after the tonguing attack.
>
> As I recall it, a message from Jonathan Cohler attributed the
> subharmonics to an overly long register tube protruding within the bore.
> He also suggested that shortening of the tube might help.
>
> Owing to frequent snags of my swab onto the register tube, I had
> been speculating about shortening the tube if only for that reason. Now I
> had a second reason.
>
> The last time I brought my instruments in for checkups, I asked the
> repair man, a local studio musician, about whether he had any experience
> in shortening the tube. He said he had already shortened the tubes on 50 A
> clarinets with generally salutary effects.
>
> At my request, he shortened my A tube a small amount, which almost
> eliminated the subharmonic buzz. I would be particularly interested in
> knowing other people's experiences, especially the list's repair experts,
> including those at the Universities of Indiana and Arizona.

In 1988 at the ICA conference in Richmond, I tried out some Yamaha Bb
clarinets in search of a new one. While doing so in the Yamaha hotel
suite, one of the technicians came in and replaced the register tubes of
the five clarinets I'd been trying with new ones which were rounded off
on the end extending into the bore. Rounded ends made the switch between
registers much smoother, for reasons I can't explain. The issue of the
length of the tubes didn't come up in that context, so I have no memory
of whether they were exactly the same length.

Any explanations from the physicists?

David