Klarinet Archive - Posting 000144.txt from 1997/04

From: Brian Ackerman <ackerman@-----.UK>
Subj: Re: Mouthpiece Facings
Date: Fri, 4 Apr 1997 19:16:55 -0500

----------
> Jerry Korten wrote
>
> Wow! Great data! I was speaking about table concavity (corrected by
Fobes,
> thanks). The stuff you are speaking about, facing curvature, is also
> important to know. I am interested to know how you get this data into
your
> computer. Were these hand made measurements?

I use the traditional method of glass-plate marked in millimeters and
feeler-gauges in .05mm increments. I feed these into the computer which
then draws the graph. You can tell a lot from this. For example, whether
there are uneven spots or weird curves. You soon get to know what looks
wrong.

> For instance I think it would be important to do a curve fit to the
facing
> curve (say a 4th order polynomial or some other model) and describe the
> curves in this way so that we could study the rate of change of
curvature.
> This would require measuring the curve at a fairly high frequency such as
> every 1 mm or so.

Using .05mm gauges gives measurements within 1mm frequencies usually,
depending on the curve. I think that if you tried to define the curves too
much you would end up with too much information to make any sense of. With
all my 100's of measurements I doubt if there are two that are identical.
One conclusion that I came to was that Vandoren mouthpieces are pretty
consistent, where as Selmer are extremely variable. Also a lot of my
measurements are on used mouthpieces, and most of them become more open
(wear) on the right-hand rail, but players do not notice this.
I can also draw new curves using mathematical splines, and then compare
them with the original. The player might for example want something with
the same length and opening but a little flatter. I can bring this up as a
graph and overlay it on the original (or perhaps another one). Visual
representation is quite useful.

Anecdote:- I once altered a mouthpiece for someone a few times. He asked
for a bit off here, then a bit more open, then a bit flatter etc. In the
end it was competely unplayable for him and we gave up. He then took it to
his teacher ( a very famous player ), who tried it out of interest. He
proclaimed he liked it, and played it in a concert that evening.

Brian Ackerman. (the answer is not out there)
UK