 The Clarinet BBoard
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Author: ron b
Date: 2000-12-19 20:47
I've seen the term here so... so often, thrown around by the experts. I've heard it mentioned, even in polite company, a time or two - among friends of course. No harm, I guessed - they still appeared to be friends after having aired their views. I usually looked on, nodding affirmatively, trying to do it somewhat knowingly, so nobody would notice my backwardness. I prefer, as so many of us do, to keep my ignorances safely out of sight, in the darkened recesses, where I can attemt to deal with them in a kindlier, gentler manner, if I can cease tossing and turning long enough, at some future time when no one's around to snicker.
But I'd like to - NO, I *need* to lay it out... I, I, oh, yes!!! Look at me! I don't know what a polycylindrical bore is ! :[ ]
Ahhhh... . . now it's out! I've said it. I, somehow, feel cleaner inside. (sob)
But, I still don't know what a *polycylindrical* bore is.
why is it so important? or *is* it?
ron b
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Author: Anji
Date: 2000-12-19 20:56
Back in the 50's (I think) Buffet R&D came up with a center bore that wasn't the same diameter (distance from one side of the bore to the other) all the way down.
This was done to improve tuning and tone. I'm not entirely sure, but I believe the bore dimensions get larger toward the bottom of the horn, in steps.
Poly-cylindrical = multiple cylinders (bore diameters) stacked one atop the next.
_____________
----------------------- ___________________
_____________ ----------------------------------
_____________
(Bore 1) (Bore 2) (Bore 3)
This is an exaggerated drawing, not to scale. I play a horn with a polycylindrical bore. I had a similar horn (same model, earlier version) with a straight bore.
The straight bore was more resitant and had more tuning problems.
It isn't a cure for all problems, but it seems to help.
I think the Archives will have more complete details if you search "Polycylindrical".
anji
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Author: Bob Arney
Date: 2000-12-19 21:08
Ron, Can I join the club? Being a basic older "restart" I wondered if it was a term only the youngsters (less than 65) invented to inflate the value of their "R13s and impress each other at glib tounging coctail parties. Actually I understand there are air wave considerations and advanced math calculations which will leave me not knowing anyway. Maybe they will take it easy on me and present an explanation that even I as a beginner can understand. My step-sister, a double PHD type, responded to my question about what she did at the Atomic research lab paused for about 30 seconds and then said---"it's no use. Whatever I tell you, you won't understand." I tell you, as I told her, "Please try."
Bob A
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Author: Bob Arney
Date: 2000-12-19 21:09
Ron, Can I join the club? Being a basic older "restart" I wondered if it was a term only the youngsters (less than 65) invented to inflate the value of their "R13s" and impress each other at glib tounging coctail parties. Actually I understand there are air wave considerations and advanced math calculations which will leave me not knowing anyway. Maybe they will take it easy on me and present an explanation that even I as a beginner can understand. My step-sister, a double PHD type, responded to my question about what she did at the Atomic research lab paused for about 30 seconds and then said---"it's no use. Whatever I tell you, you won't understand." I tell you, as I told her, "Please try."
Bob A
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Author: ron b
Date: 2000-12-19 21:46
Bob, you're welcome - anytime. Here, please sit beside me and compare notes (!) :o]
I'm a 65 year old restart. I've been around music most of my life, one way or another. I repaired horns in my younger days and have taken it up again on a small scale since I retired. In the 50s and 60s I was quite active as a player. For various reasons I let it slide into total dormancy for a long time. I took up the horn again as part of my renewed interest in repair work. I have nearly always maintained my own instruments.
While I was in the Air Force in the late 50s some guys were talking about new concepts in clarinet manufacturing, i.e. polycylindrical bores. I understood, at that time, that the bore, in different places along its length would vary in diameter. It was supposed to improve intonation and overall playability. It was an interesting idea but one I did not persue. I played a regular horn (an Albert system, by the way) that worked just fine. Some of the guys, four of five I think, had gotten the newer instruments and were playing them about the time I was discharged. So, I didn't get any first hand experience with those. I was curious about them though and always thought that 'sometime, somewhere' I'd find out more. Well, I never did.
Now, when the term comes up I feel like a total dunce, like my education took a detour somewhere and I never quite caught up with all the new developments. The instruments I work on are school horns; student grade, plus or minus. So, really, when polycyl horns are mentioned I feel totally out of it. I'm hoping someone, kind and patient, can fill us in, Bob. I'm willing and ready to listen as I know you are.
Maybe others will benefit by joining us. Here, let me scoot over a bit.
ron b
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Author: bob gardner
Date: 2000-12-19 22:49
is teh r 13 the only one that has a poly bore? or is in now standard in all horns.?
I have a labanc, a selmer and an r13. Which would have it and who is lacking?
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Author: Mark Charette
Date: 2000-12-19 23:32
No. The polycylindrical bore is used in many of the finest clarinets (not all - but many). As the name really says - poly (many) cylindrical bores. The drawing by Anji shows the steps. They are pretty abrupt - but the steps are very small. Somewhere here on the BBoard or in the Klarinet archives is the approximate place on an R-13 where the bore changes size. Try searching around.
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Author: Slownoise
Date: 2000-12-20 08:59
The Buffet company says that the poly-cilindrical innovative bores were developed by Robert Caree: the R13 bore in 1950 and the RC bore in 1975... then leading to the launch of the professional "Festival" and "Prestige" models.
Today, the RC model bore has the upper joint poly-cyndrical, and the lower joint and bell conical, while the R13 model has a full poly-cyndrical bore, as well as the
Elite model.
This is all I know. I have seen a picture of these bore once; but I can't recall the exact features.
Slownoise
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Author: Gordon (NZ)
Date: 2000-12-20 10:24
One version or the phenomenon I came across - a very well respected make but I've forgotten which - seemed to consist of the barrel having a quite significantly smaller bore than the mouthpiece or adjacent body.
I is contrary to my very basic notions of acoustic theory that a SUDDEN step in the bore diameter could be a good thing. This essentally was a step made of right angles. It would not have jarred my mind if the bore had a smoothly shaped 'neck'.
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Author: Yusuf Zaid
Date: 2000-12-20 20:09
I'm not too sure about this but I believe the small steps in the bore, widening it fractionaly, has an effect on the standing waves. These are the waves that are reflected back up the bore from the bell opening. It's all very complicated. It's a science in itself. Very similar experiments are done with 2 stroke motorcycle exhaust pipes as the standing waves effect the overall performance of the engine.
The standing waves, in turn, have an effect on the sound waves in a wind instrument. Modifying them to produce specific qualities in the end sound. This might have the effect of sharpening or flattening specific frequencies.
The standing waves travel back up the bore and, when they reach the mouthpiece, are reflected back down the bore with the sound wave being produced by the reed but at a 90 degree difference ( there's a word here I want to use but can't, for the life of me, think of ). If the bore is stepped then this has a, sometimes, quite drastic effect on specific frequencies.
Phew, I had to dig deep into my brain for that one. It's years since I studied physics. But I think I'm on the right track.
If you go to the library and look up acoustics in a pipe it'll probably explain it better than I just did.
Maybe there's someone out there who can explain it better.
Yusuf
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Author: Yusuf Zaid
Date: 2000-12-20 20:12
There's a better explanation of it in Jack Brymer's book, with diagrams.
Yusuf
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