Klarinet Archive - Posting 000132.txt from 1995/04

From: CLARK FOBES <reedman@-----.COM>
Subj: Re: A good question...
Date: Mon, 10 Apr 1995 08:22:29 -0400

You wrote:

>
>Is there any reason that the 'A' just above the staff is the first note
>(while going up the chromatic scale) that has a tendency to refuse to
>sound with good tone from the very start of its attack? It seems that
if
>I have a reed that does not respond at its optimum level in a certain
>octave, the 'A' is at the lowermost or uppermost end of that octave.
>
>I doubt that the problem is in my playing (I'm working on my Master's
in
>Clarinet Performance). Could it be characteristic of the six-finger
>instruments?
>
>Incidentally, I seem to recall a similar problem on my tenor recorder.
>
>Thank you.
>Robert
>
>This problem is very common on Buffet A clarinets, but not so common on
the Bb. The best position for the register tube to excite the interval
of the twelfth is one third the distance between the tone hole and the
mouthpiece (The calculation is probably made from the top of the bore
inside the mouthpiece) If you look at your clarinet you can readily see
that the most appropriately placed tone hole is the one that produces
the Bb/F. In most cases this interval is the most in tune and the
twelfths become wider as you approach either the bell or the mouthpiece.
This would be especially true if the tube remained perfectly cylindrical
and there was no bell flare.

Even more problematic is the fact that the register tube must
function as a tone hole for throat Bb. The diameter is not really wide
enough to produce a clear Bb, but if it were it would not be
sufficiently small enough to excite the twelfth. I have done a lot of
experimenting with register tubes and have pretty much come to the
conclusion that Buffet has a pretty good compromise. Both the RC and the
Festival models have the tube placed about 2mm higher and the problem
with the resistant "A" seems to be much less.

In the case of the Buffet A clarinets I think that this area is
in need of attention on the R-13 models. The configuration of the upper
bore is slightly different than the Bb and this may have an adverse
acoustical effect as well. I usually cut the "A" clarinet tubes .020".
This helps the stuffy A and brings the Throat Bb up in pitch a bit. If
you choose to shorten the register tube on your A clarinet be precise.
Too much shortening will cause the left hand clarion notes to rise in
pitch.

I have also had some success with enlarging the D/A tone hole
slightly. This has to be done with a special tool, so don't try this one
at home.

Because the problem is rare on Bb clarinets I would suggest
making certain that :

a: the tone hole is clean
b: the register tube is clean
c: the instrument is sealing properly

and

d: if you are not using a reverse cone tapered barrel already
try one. This can have a very positive effect on focusing
in tones in the upper left hand clarion.

Clark W Fobes