 The Clarinet BBoard
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Author: Liquorice
Date: 2005-04-06 09:21
I've got a 67mm Chadash barrel. It plays a little bit flat with my instrument, so I want to get it shortened by about 1mm. It's a reverse taper bore (as far as I understand), so does it matter which end I shorten it at? (i.e. mouthpiece end or other end?)
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Author: Gordon (NZ)
Date: 2005-04-06 09:54
Most barrels have a more sudden outside-diameter taper at the lower end, so if you shorten it there may be a step in diameter from the timber to the metal ring - assuming it has a metal ring - which is not aesthetic.
I cannot answer your question regarding the bore though.
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Author: Alseg
Date: 2005-04-06 12:59
When dealing with stock barrels, traditionally, the shortening is done at the mouthpiece end .
BUT...........
When shortening taper barrels I like to reassess the bore dimensions
and adjust them accordingly. The ratio of the diameter of the mouthpiece exit bore to the diameter at thestart of the barrel bore should be maintained.
Former creator of CUSTOM CLARINET TUNING BARRELS by DR. ALLAN SEGAL
-Where the Sound Matters Most(tm)-
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Author: Don Berger
Date: 2005-04-06 18:24
Good comments, Alseq, I avoided having to cut an [already short] sop C barrel by shortening a fair [but NOT my best] mp by 1-2 mm, it worked well. I have pondered your mention of "ratio" mp tenon/barrel top, shpuldn't it be exactly 1.000 [same], I just cant see any advantage in having a step at any point above the bell. 'Course, my fluid flow knowledge derives from Chem Eng pipe-sizing, faster, with Reynolds# characterization !!, not very applicable here, granted . Don
Thanx, Mark, Don
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Author: donald
Date: 2005-04-06 19:36
the enquiry was about a Chadash Barrel
they are one of the (now) many utilising a "reverse conical bore"
there is much information available regarding the reasons/advantages for this kind of bore (not to suggest that a cylindrical bore can't also be good/desirable). I imagine that many of the barrels by the much discused Backun are of this type.
given that you can't add material, only take it away, shortening the barrel will adjust that ratio (entry-exit), probably reducing the resistance, possibly brightening the sound and theoretically widening the left hand 12th intervals (but by a very small margin). This may or may not have a possitive effect.
keep playing the good tunes
donald
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Author: Ken Shaw ★2017
Date: 2005-04-06 20:17
I think cutting down a reverse-taper barrel at either end could be problematic. It starts at a particular diameter and ends at another, and any alteration to the length will affect one measurement or the other. A barrel made to a shorter length would have a slightly more severe taper throughout its length.
Also, many barrel makers put a slight "hour-glass" profile in the bore. The location of the narrowest point is critical, and any change in the barrel's length will throw it off.
I know from personal experience that a skilled barrel maker can adjust the bore profile to work best on your particular mouthpiece and instrument. I think it would be worthwhile to visit a barrel maker and get a custom match.
Ken Shaw
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