 The Clarinet BBoard
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Author: Filettofish
Date: 2014-08-23 00:42
Hello again, just received my new/used A R13 in the mail, pulled it out the case and it plays with ease, other than a rather noticeable air leak around the chalumeau C/C# area. After testing both body joints for suction, it appears there is no leak in the padding, however there is still an extra bit of resistance when articulation chalumeau C/C# and clarion G/G#. I tested my mouthpiece and reed on my Bb where they play perfectly. Any thoughts on what the problem could be?
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Author: maxopf
Date: 2014-08-23 01:09
How far above the tone hole is the C#/G# pad when you press the key? Maybe it's not a leak, but rather the pad isn't lifting up far enough. Just a guess.
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Author: Filettofish
Date: 2014-08-23 01:32
Pad seems to lift to the standard height. I don't think that's the problem. It seems to be in the lower body joint. I only hear air when playing with the lower joint attached. If I remove it, the very sharp C you get when fingering a C on the upper half of the instrument sounds full.
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Author: saxlite
Date: 2014-08-23 01:45
If the joint passes the suction test, there still may be some misadjustment of the crow'sfoot. Try blocking the lower end with a cork ( or your palm ) and give a puff of air into the upper end.This is a much better test for leaks and closer to actual playing conditions. The suction test tends to pull the leaking joint closed and can give a false OK to a small leak. Hold the RH Ab/Eb key closed if need be.
Jerry
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Author: kdk ★2017
Date: 2014-08-23 01:57
By "air leak" I assume you mean that you hear a lot of noise or hiss. That particular tone hole is prone to this kind of stuffiness because it is placed in the wrong spot. For best intonation it should be located right in the middle of the tenon-socket of the middle joint with a larger tone hole. Manufacturers have generally moved it up above the joint and then compensated for the sharpness of the shorter air column by making the tone hole smaller. It's mostly that smaller tone hole diameter that causes C#/Db4 and G#/Ab5 (it's twelfth) to be stuffy and harder to control.
If the pad doesn't open enough, of course, it will make the problem worse. You can't enlarge the tone hole itself without raising the pitch too much to be a good trade-off (which is the reason for the problem in the first place). Often a repair tech will undercut the hole a little, allowing a slightly larger, more tapered escape for the air at that hole. This can free the response and not raise the pitch nearly as much as actually boring the outside of the hole itself bigger. It will still be a compromise, because you can only do so much before the pitch gets too sharp, and also you have to be careful that the twelfth (G#/Ab5) doesn't get sharper than the C#/Db4. It's a delicate compromise that is best done slowly in small increments, but those notes can be markedly improved.
In my experience (others may well differ) I have found that an A clarinet slightly exaggerates this and other pitch/response compromises. Your Bb may have been designed slightly differently or was already undercut to solve the problem before you got it (it's part of some techs' setup procedure).
Karl
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