 The Clarinet BBoard
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Author: mike
Date: 2000-10-30 18:04
I vaguely remember seeing something like this a while back, but I'm not sure.
I was playing a long rehearsal on bass yesterday afternoon. Near the end, I started having some real problems with the clarion F and above. I could not tongue the notes (on several different reeds and 2 mouthpieces...) and if I slurred up to them, they would speak, but were very unstable.
I pressure tested the upper joint and found the the throat Ab pad to be leaking pretty badly and the A to be leaking some. I suspect that this is due to either the tone hole or the pads becoming water-logged and swelling. Is this correct? (Note, I tested it again late last night and the seal was much better. Also it was neither particularly cold nor hot in the room, and I don't see any big cracks in the tone holes in question).
Would replacing the pads with cork be a good solution to the problem? Or is that considered to be a no-no on the bass?
The instrument is an intermediate Buffet (1180?). Thanks for your help, Mike
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Author: Al
Date: 2000-10-30 19:38
Mike,
It's the "sudden" part that I don't understand.
If the throat Ab was leaking badly, you wouldn't get many notes in the clarion register.
Check around the clarion F and also get those throat tone keys sealed properly.
This symptom also occurs when the bridge between sections is not lined up properly. It will affect both the F and the fork Bb pad. Could you have inadvertently misaligned the joints at some point?
Best wishes,
Al
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Author: mike
Date: 2000-10-30 20:28
Nope. I checked the alignment. That's always the first place to look, though that would either screw up the clarion BELOW the F or the fork Bb would speak poorly, depending on the rotation.
Leaks are funny things. The entire chalmeau played just fine. But to get the upper clarion, I had to push on the Ab pad. Most likely, the node that the leaking Ab pad would tend to create in the standing wave patterns of the notes from B-F was far enough away from the overtones of those notes that I could still drive them. The F# and G were too close to the overtones and that's all I could get.
Most of us are fairly proficient at this without even realizing it. We tend to "vocalize" the notes that we play, and we can compensate for small leaks created by slightly out of repair instruments (and the ever so occasional botched fingering).
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Author: 'nifer
Date: 2000-10-30 23:09
hi! if the register key got moved somehow (your middle joint or neck SLIGHTLY moved it could throw off the mechanisim causing certain keys to open when others dont.. when you pressure test again get someone to help you and test the instrument together..
'nifer
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Author: Don Berger
Date: 2000-10-31 02:53
Reading your word "sudden" , my first thot was that one of those !@#$%^ little bits of cork , so necessary to proper key action, had come off unnoticed, likely one associated with register keys [single or double?]. OR, did a pad come loose, maybe on a higher trill key? Sure hope that your BC didn't develop a crack. Keep hunting, Don
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Author: Steve Hartman
Date: 2000-10-31 12:05
It's possible that the A pad swelled because of moisture. Is there a little bit of play between the A and G# keys? If not, there should be, because a swelled A pad could cause the G# to leak slightly.
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Author: Lelia
Date: 2000-10-31 18:01
THe fact that this happened so suddenly on the A and Ab keys makes me suspect that maybe that little set-screw on the top of that crossover mechanism has worked loose. It's a very fine adjustment between too loose and too tight. If it's wrong, one or both pads won't seal. I had a miserable time with that adjustment on the Lerue clarinet in A I worked on recently. Some clarinets are more finicky about it than most.
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Author: SusieQ
Date: 2000-11-01 20:57
Hi Mike,
I am no technician, but I had a similar experience with my bass clarinet. During a concert, my bc quit working completely, not one note would come out. It was real sudden and luckily it was during the second to the last piece and I didn't have any critical parts. The culprit was the spring on my A key, it was weak and finally snapped. One little piece of metal can sure screw up an instrument in a big hurry. Maybe you have a loose or weak spring somewhere up by the F, G and A keys? Good Luck!
SusieQ
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