 The Clarinet BBoard
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Author: MiamiBeach
Date: 2023-04-17 18:15
What does polycylindrical mean? And what effect does it have on the sound of a clarinet?
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Author: ACCA
Date: 2023-04-17 19:15
The following pages have a good overview:
https://hansonworld.co.uk/bore-shape-and-size/
https://www.clarinet.dk/content/show_content.php?cont=eu&lang=en&id=181&instr=cla
https://clarinetandflute.com/blogs/news/buffet-r13-vs-buffet-rc
enjoy
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Author: Micke Isotalo ★2017
Date: 2023-04-17 20:36
From the Hanson page I understand "polycylindrical" as a bore with a number of cylindrical (straight) sections of different diameters (thus with a more or less pronounced step between these sections).
From the Lohff & Pfeiffer page however, I understand "polycylindrical" to be conical ("the bore is wider at the barrel side and becomes slowly smaller").
So, which description is correct?
Surely the bores of all kinds of soprano clarinets (English, German, French) are gradually widening from a point more or less close to the bell and towards the bell, but I don't think the term "polycylindrical" is at all related to that lower part of the bore.
If the Hanson description is correct, how pronounced is the step between the cylindrical sections of different diameters? Can they be seen by looking inside the bore, or felt by dragging a finger over the step (provided such a step is reachable from the end of a joint)? Or are they so subtle that only a measuring tool could detect them? Also, roughly where along the bore are these steps usually located?
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Author: Micke Isotalo ★2017
Date: 2023-04-18 20:59
As a follow up, I would believe that Hanson as a clarinet manufacturer is providing the correct description.
Concerning the gap between cylindrical sections of different diameters, could it be that simple that the only gap is between the joints? That is, the lower, cylindrical part of the upper joint bore has one diameter, and then the upper, cylindrical part of the lower joint bore has another diameter? If also the barrel bore is cylindrical, with a third dimension, there would be three different cylindrical diameters, and thus the term "polycylindrical"?
From a manufacturing perspective this would probably make most sense, since machining several cylindrical diameters within the same joint (or barrel) would probably be a quite demanding task.
Post Edited (2023-04-18 21:49)
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Author: clarnibass
Date: 2023-04-19 09:14
>> From a manufacturing perspective this would probably make most sense <<
Not necessarily, as long as you don't have a larger diameter in the middle than at both ends, which isn't the case anyway for polycylindrical bores. At least some manufacturers make the final bore (before some sanding/polishing) with a reamer, so it's a "simple" case of making the reamer shape correct. The difference in diameter on polycylindrical bores is small enough that you could use the same pre drill.
At least some polycylindrical bore clarinets have the different diameter throughout the sections, and same for some barrels. It is not only the different sections that have different diameters.
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Author: Luuk ★2017
Date: 2023-04-19 14:17
Be aware that the differences in diameter within a joint of a poly cylindrical clarinet are about 0,5 mm at most (excluding the flare at the bottom of the right hand part). Barely visible, especially since the different diameters are joined by tapers. For more info, see http://www.sfoxclarinets.com/baclac_art.htm and http://www.sfoxclarinets.com/BenclartI.html. Bore measurement graphics can be found on these pages.
This subject has been discussed many times before on the BB, did you do a search?
Regards,
Luuk
Philips Symphonic Band
The Netherlands
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Author: donald
Date: 2023-04-19 15:47
Having spent a lot of my life looking down the bore of various Buffet Clarinets I can say that I have on some clarinets been able to actually see the different "stair steps" (on some barrels, for instance the Zinner barrels that Mike Lomax sold, you can get a visual fix on the central cylindrical section and cone/reverse cone sections of the barrel bore).
The R13 design has 3 cylindrical sections in the top joint (correct me if I'm wrong, it might be 4?), and one main cylinder in the lower joint. The sections are different by very small tolerances, think the thickness of a piece of paper or a postage stamp, and the "stair-stepping" between each section may be obscured by the final ream/polish depending on various factors (even down to, WHO was at work that day and what mood were they in).
I've seen at least two or three R13s over the years where the steps were not visible if you looked from the top down, but if you looked from the middle joint UP the bore (with light at the end of the tunnel) the steps were clearly visible.
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Author: pukalo
Date: 2023-04-19 23:50
donald wrote:
> Having spent a lot of my life looking down the bore of various
> Buffet Clarinets I can say that I have on some clarinets been
> able to actually see the different "stair steps"
I tried this on my 1973 R13, and I was able to just barely see a faint ring in the lower joint towards the end, just before the low F-sharp tone hole, as well as one faint ring in towards the end of the upper joint
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