Klarinet Archive - Posting 000850.txt from 1998/07

From: reedman@-----.com
Subj: [kl] The Selmer CT vs Buffet r-13
Date: Thu, 23 Jul 1998 15:33:10 -0400

I am so pleased to see the Francois Kloc has come on to the list!
Thank you Francois for your clarifications regarding tone hole undercutting
etc. I hope you will continue to offer your comments.

As most of you know, through my work on barrel and mouthpiece design
and 22 years of repairing and tuning clarinets I have a great interest in
the acoustical design of the clarinet.

This discussion is directed primarily toward the design of the Selmer
Centered Tone Clarinet "CT". I have one in the shop right now that I will
overhaul this week. The serial# is P9050, made in 1952-54. There are some
very interesting aspects to the design of this clarinet that are worth
mentioning.

First, when we begin a discussion of bore size we must , in most
cases, discuss "nominal bore size". Because most clarinets in this century
have some type of taper in the LH joint and an extended flare in the RH
joint the only cylindical portion is that area in the middle of the
instrument. Also, on older instruments the bore may constrict or expand at
the tenons. I take measurements for the upper joint about 1" or 25mm into
the bore from the middle tenon end. I take measurement for the lower joint
also from the middle tenon end. This is the area of the "nominal bore".
On this CT I measure .587" or 14.91mm. The top of the upper joint
measures .600" or 15.24mm. This last measurement is very accurate because
the "CT" has a metal tenon end so that the bore there is realtively
immutable. Contrast that to a standard R-13 ca 1985. Nominal bore is .577"
or 14.65mm and the top of the upper bore is .590 or 14.98mm. This last
measurement may be slightly larger than standard. I suspect that the wood
has changed over time. Now comes the part that is most interesting to me:
Tone hole, Barrel and Bell design.

The CT has completely unfraised tone holes. The one exception was the
A/E tone hole in the lower joint. My understanding is that most clarinets
up until WWI were made with small bores and fraised tone holes. The larger
bored unfraised clarinets were an innovation of Henri Selmer. Selmer
remained dedicated to this formant until the 1960's when they introduced
the Selmer Series 9* which has fraised tone holes.

On page 45 of "Clarinet Acoustics" by Lee Gibson the
author discusses some aspects of bell flare design as it relates to bore
and tone hole shape. He states:

"The larger bores of the early nineteenth century reappeared in the
second quarter of the twentieth century and encouraged in the larger bored,
unfraised soprano clarinets of Henri Selmer the revival of Ivan Mueller's
strictly concical bell of a century earlier".

Not only is the bell on the CT perfectly conical, the bore is larger
at the top than the Buffet, smaller at the bell end and longer than the
Buffet. Another difference is that the bore at the top of the bell matches
perfectly the end of the bore flare of the lower joint. This lack of
"choke" (as in the Buffet clarinets) has a distinct effect on the sound of
the instrument AND the tuning.

At the other end, the Barrel is quite different than either standard
Buffet design or Buffet/Moennig. A typical 66mm Moennig barrel has
dimensions of .489 at the upper end and .578 at the lower end. This "CT"
clarinet is 66mm long, .605" at the upper end and .595" at the lower end.
Quite large!

Intuitively one might think that a large bored mouthpiece would work
well with this instrument. I don't have a Selmer mouthpiece from this era,
but my recollection of those I have measured have bores that are large
DIAMETRICALLY, but are rather short. They play quite sharp on contemporary
instruments . Essentially a SMALL bore mouthpiece. This makes sense. If one
plugs in a standard contemporary mouthpiece into a Selmer CT the pitches in
the throat tones are very flat because the overall volume of
mouthpiece+barrel is too great. This can be somewhat obviated by using a
shorter reversed cone tapered barrel in the style of FOBES, MOENNIG OR
CHADASH. One of the advantages of smaller bored reverse cone barrels on
Buffet clarinets is that it lowers the upper notes of the 2nd mode of
vibration. These being the clarion notes in the left hand. That becomes a
problem on the CT, because these tones are already low.

As an interesting aside, I have noticed a large discrepency in the
tuning and lengths of Kaspar mouthpieces. There is no doubt in my mind that
both Franks Kaspar were masters of their art. WHY then do we encounter such
wild deviations in pitch. I think that as we look at the period the the
Kaspars were most productive we can find the answer. During the 40s, 50's
and 60's Selmer was a very popular instrument. More popular than Buffet,
actually. Certainly the Kaspars (both fine repairmen as well) knew the
differences in Selmer and Buffet design and were capable of making
mouthpieces for either. I have a Cicero Kapar 13 with a very short bore and
is decidedly shorter (overall) than the standard 89mm required for Buffet
clarinets. The tuning is excellent on this old CT. BINGO!!! The Kaspars
were making mouthpieces for Buffets and Selmers and KNEW how to accomodate
the different acoustical designs.

Clark W Fobes

Clark W Fobes
Web Page http://www.sneezy.org/clark_fobes

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