 The Clarinet BBoard
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Author: Micke Isotalo ★2017
Date: 2026-09-26 13:01
Is it normal for the throat G# key on a bass clarinet to open at a pressure test (blowing into the bore of the top joint with the keys and bottom end closed)? In this case a moderate pressure, not blowing as hard as you can, opens the key.
On a well adjusted soprano clarinet none of the keys of the upper joint opens at a pressure test, no matter how hard you blow (the feeling is as blowing into a bottle) - but are bass clarinets different?
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Author: kilo
Date: 2026-09-26 15:40
I'd guess that the spring is weak but as long as the instrument is playable it doesn't seem like anything to be concerned about.
I tested all three of my basses. The Royal Global Max remained tight as a drum no matter how hard I blew. The Selmer Model 30 leaked a bit under high pressure but the key itself didn't budge. The Backun Alpha would open with moderate pressure but this has never been a problem when playing.
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Author: Micke Isotalo ★2017
Date: 2026-09-26 15:51
I actually also have an Alpha. My problem is some sensitivity for squeaks in the right hand first register (from about B natural down to low G). This concerns primarily accentuated notes in forte, with a breath before. With a 1980's Leblanc I didn't have this problem (but instead with the middle clarion notes, which however are very good on the Alpha). I will try with blocking the throat G# key and see if it makes a difference, but have to wait until tomorrow (everything else seems airtight on the Alpha, including the register vents).
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Author: kilo
Date: 2026-09-26 17:10
As I understand, the Alphas are set up with the lightest effective spring action. You could certainly bend the spring a little, carefully, to increase the strength. I don't think that the throat G# key, usually activated by the side of the hand instead of direct finger pressure, needs to be set for as light a touch as some of the other keys.
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Author: rmk54
Date: 2026-09-26 17:30
Before you start bending springs (which could break if you are not careful) why not close off the pad with a rubber band to see if that alleviates the problem?
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Author: Chris P
Date: 2026-09-26 18:28
While pressurising the bore isn't going to happen in a real world playing scenario, closed standing keys should always have stronger spring tension to ensure the pads remain closed under that spring tension alone. Given the weight of the throat G# key on basses (particularly ones with Buffet style keywork which is a bit of a hefty lump), the spring tension also has to be relative to counteract the dead weight of the key.
If you're finding this key sprung too lightly, then it won't do you any harm in beefing up the spring tension and even better still if the spring can be unhitched while the key is still in situ if there's enough clearance under the spring cradle. Depending on the quality of the needle springs, some cheap ones don't retain any spring tension no matter how much of a bend you put in them and some can be brittle as anything and snap clean off if you overdo it.
If the spring is maxing out and still not giving the required closing force or just losing all the tension you put in after hitching it back in place, then you're best replacing it for a better quality one of the same gauge or going up in gauge by 0.5mm diameter and will have to ream out the spring hole in the pillar to do that. Use the blunt end of the oversize needle spring as a broach by grinding a flat on it and holding it in a pin vice to ream out the spring hole. You'll either have to rotate the pillar or remove it completely to gain better access to do this.
Former oboe finisher
Howarth of London
1998 - 2010
Independent Woodwind Repairer
Single and Double Reed Specialist
Oboes, Clarinets and Saxes
NOT A MEMBER OF N.A.M.I.R.
The opinions I express are my own.
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Author: clarnibass
Date: 2026-09-27 10:45
>> If the spring is maxing out and still not giving the required closing force or just losing all the tension you put in after hitching it back in place, then you're best replacing it for a better quality one of the same gauge or going up in gauge by 0.5mm diameter and will have to ream out the spring hole in the pillar to do that. <<
I suspect you meant 0.05mm
So no one accidentally reams out a spring hole by 0.5mm...
As far as the actual issue, as other suggested, best to hold it closed somehow (rubber band, string, human person, etc.) and see if it happens then too.
When it's borderline, sometimes the speed and momentum from the key springing back can help it close better. Meaning, it might be best to close it as slow as you can, then when the problem happens, have someone immediately hold it more firmly and see if the problem goes away. If it does, then it's a clue that it might be the reason but it's not 100% guaranteed. The problem could be something that is caused (even if partially) by your playing (e.g. you are blowing slightly differently, the way your fingers are placed on the keys, etc.) then just stopping and playing again can change that.
Post Edited (2026-09-27 11:02)
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Author: donald
Date: 2026-09-27 11:52
I second rmk54's suggestion. Also note- if the spring is set really lightly, then even a slight touch from the hand/index finger will open the key slightly. With a bit more spring tension, you may be able to touch the key without it opening, and if you're used to this then the lighter spring presents a problem.
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