Klarinet Archive - Posting 000122.txt from 1997/04

From: Jerry Korten <Jrykorten@-----.COM>
Subj: Re: Mouthpiece Facings
Date: Fri, 4 Apr 1997 10:51:48 -0500

In response to Brian Ackerman ....

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?

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.

Do you have a special instrument to measure the facings? I am thinking about
either renting time on a CAD input device (non contacting measurement
device). Or creating a device which has an output that could be digitized in
order to measure the facing curvature. But I hate spending hard found time
reinventing the wheel as it were.

The process of refacing a mouthpiece is so "low fi" that it hardly qualifies
as a science. However I think the mouthpiece manufacturers are set up with a
tooling jig to do this in order to get the consistency they achieve.

It is interesting that the facing length you report for the B45 is so
different from what Vandoren reports. Was this mouthpiece refaced?

Thanks for the info.

Jerry Korten
NYC

>I have many hundreds of mouthpiece lays on a computer program. It graphs
>out the lay and compares them etc. It was very difficult to compare so many
>facings and reach any conclusions. One answer was to compare the amount of
>curve in relation to a straight line with the same tip opening and length.
>This does not result in any magic answers, as peoples opinions of the
>perfect facing will vary, but it does offer a way of measuring and
>comparing the degree of curve on facings with the same length and opening.
>The point measured is half way along the length, measured in 100ths mm,
>compared to a straight line. The larger the measurement, the more curved is
>the facing. I call it the curvefactor and have given just a few examples.
>MOUTHPIECE TIP(100ths.mm) LENGTH(mm) CURVEFACTOR
>Zinner 3 90 25
> 15
>Selmer C85/105 105 16.5
>19.1
>Vandoren 5RV 105 17
>21.6
>Yamaha 4c 105 21.5
> 27.8
>Hite (signature) 110 16.8
> 18.8
>Pyne E 110 18
> 21.3
>Vandoren 5RVL 110 18
>21.3
>Selmer C85/120 120 19
> 24.4
>Vandoren B45 120 16.7
> 20.8
>B&H 1010/2 120 20
> 31.3

>Any comments would be welcome.
>Brian Ackerman
>UK

   
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