 The Clarinet BBoard
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Author: Clarineteer
Date: 2012-12-23 07:14
Can someone please tell me what specifically is the difference between a pre R13 from 1949 and todays R13. Thanks very much.
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Author: John Peacock
Date: 2012-12-23 18:22
Since the early to mid 1950s, R13s have had a 'polycylindrical' bore. I always found this a bit of a confusing name: it means that the upper joint is overall conical, being wider at the top and reaching its narrowest where the upper and lower joints join. The reason that it isn't just called a 'conical' bore is that the narrowing isn't uniform: it tends to be concentrated at particular regions down the bore. But if you look down it, you certainly don't see abrupt steps from one cylinder to another, so it is a continuous narrowing. For more detail on this, see http://www.sfoxclarinets.com/Basic%20clar%20acoustics.html
The amount of narrowing is about 0.25 mm, from about 15.0mm at the top of the top joint, to 14.75 at the bottom: Not a great deal, but easy enough to measure with a caliper. Pre-R13's, in contrast, have this joint much more nearly cylindrical. There still seems to be a bit of a taper on them, but more like 0.1mm. It's this substantial narrowing of the bore that is the real diagnostic of a modern R13. The mounting of the throat Gsharp key and the trill-key guide changed over time, but there was a period of several years around 1950 when things were fluid and some instruments emerged with old-style keys but the new bore.
But both the old and new instruments were called R13s. Not an official Buffet designation originally, but a catalogue number due to Carl Fischer of New York. So the name just meant "whatever professional clarinet Buffet is making at the moment", and the term 'pre-R13' is strictly incorrect, even if it's generally clear what it means.
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Author: Caroline Smale
Date: 2012-12-23 19:00
My understanding of the R13 polycylindrical bore is that it is a combination of 3 (possibly 4) cylinders of gradually decreasing diameter.
These are indeed concentrated at the top of the upper joint and seem to end somewhere between the A tonehole and the thumb bush.
So the bore is cylindrical at one diameter to approx the speaker hole then reduces but stays cylindrical until about the thumb bush and then continues as a plain cylinder of 14.65mm to the bottom of the joint.
Unfortunately my bore guage will not reach all parts of the bore to be more precise about the lengths.
The steps are indeed blended into each other so do not show as an abrupt change however on some bores in the right light it is just about possible to see the changes.
Some earlier Buffets had a purely conical section at the top of the bore before changing to a parallel cylinder for the rest.
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