Klarinet Archive - Posting 000748.txt from 1996/02

From: CLARK FOBES <reedman@-----.COM>
Subj: Re: Mouthpieces: Tonal concept, etc.
Date: Sun, 25 Feb 1996 03:29:35 -0500

You wrote:
>
>Clark,
>
>Very interesting comments. Can you expand on one point you made
please
>
> "2. The volume of the chamber has an inverese relationship to the
>volume of the bore."
>
>What relationship is this? Do you imply that a small chamber should
>have a large bore? If so, where do German and English mouthpieces fit
>in which, to my untrained eye, both have large chambers and large
>bores?
>
>John Jarvie
>j.jarvie@-----.nz
>

GOOD POINT! I think that I probably should have expanded on that
more.

Let me back pedal a bit if you will so that I don't get myself into
trouble!

All of the work I have done is for Buffet clarinets and that
certainly qualifies my data. The statement would have been better
stated, "For proper intonation at a given overall volume the volume of
the chamber is an inverse relationship to the volume of the bore". The
caveat here is that this works in a pretty narrow range of values. And
as I think about this I suspect that there is most likely an optimal
value for the bore regardless of shape.

This last observation leads me to believe that the more important
relationship of chamber to bore is proportional. After some crude
measuring of several mouthpieces this apears to be a ratio of about 1
to 2. (Chamber is 1/3 of the overall volume). This seems to be proven
out by experience when I have overbored a mouthpiece. I can bring back
the resonance by opening up the side walls, but the pitch goes down

The current German blanks made for French clarinets that seem to be
in vogue are an exmple of a slightly smaller bored mouthpiece with a
deeper chamber. The overall tuning is about right, but the
relationships in the various registers are not quite what I like. They
also require a fairly short close facing. (That's another subject!) .
On the other hand, most Kaspars have a larger bore with a small
chamber. I'm in between.

Also, remember that the overall length of the mouthpiece affects
the overall volume. Consequently one could make a very large bore
diametrically but correct the volume by shortening the mouthpiece. This
effectively shortens the bore. A chamber can have a aweeping and deep
shape, but then the distance between the walls must be compressed to
retain the correct volume. (See Gigliotti mouthpieces).

The older Selmer mouthpieces are a good example of a properly
proportioned mouthpiece regarding playablity and response, but they
have a small (short) bore and small chamber and play sharp

As my dad use to say "There's more than one way to skin a cat".

Clark W Fobes