 The Clarinet BBoard
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Author: graham
Date: 2003-08-29 12:03
I 've had this problem for quite a while and two techs have had a go at solving it to no avail, so I wondered if anyone had any experience of it and ideas for a solution (or just ideas, whether or not with experience).
My bass was designed to go down to E flat. It now has an extension to give more range, but the problem in question arose before the extension was made and is present whether the extension is on or off. However the problem was not always there and started occuring some time after I had it overhauled.
When I play from bottom F downwards (and C downwards in the upper register), the A flat/E flat key vibrates in such a way as to produce an increasingly distorted or modulated tone. This not merely a buzzing which irritates the player (and not the listener); it is a distortion to the sound being produced. It seems as though the key opens and shuts extremely rapidly thus causing a fluttering on/off sound. I have not found that the key blows open fully (thus removing the tone altogether). I know it is this key because an elastic band on it solves the problem (or holding it shut in any way). In fact, it seems that the touch of a finger on the key merely to damp its vibration is sufficient to stop the problem and there need be no actual downward pressure on the pad. I do not think it is a resonant frequency as such as the problem applies to all notes which close pads below this key (suggesting to me it is a pressure issue).
The first tech checked the seating of the pad and that was fine. The pad is a white leather fairly hard and thin pad, but in top condition. There appears to be nothing amiss with the tone hole it rests against. She fitted a stiffer spring and it is quite stiff enough for what you would expect, but that had zero effect on the problem. She added some glue (or whatever) to the point where the pivot screws into the body because she thought it might be vibrating rather than the key. No effect. When I say no effect, I mean none whatever; not even a slight reduction.
The second tech took the view that, great as the pad was, it might be too hard and that this exacerbated any vibration problem. He fitted a softer leather pad which was hoped would cope with the vibration by flexing with it and keeping the tone hole shut at all times. I have noticed a difference from this. The problem is almost entirely eradicated in the upper register (where before it was worse) but is now a good deal worse in the lower register. He did no other tinkering in this respect.
I am at the stage where even fairly unlikely ideas are worth considering as long as they don't damage the instrument! Hope some of you can help.
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Author: DezzaG
Date: 2003-08-29 13:25
How about a stronger spring so it doesn't blow open? Is it stainless steel they use when they want stronger than blued springs?
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Author: David Spiegelthal ★2017
Date: 2003-08-29 13:34
DezzaG is correct, the spring is too weak --- this is a VERY common problem on bass clarinets. Unfortunately that particular spring is the toughest one on the entire instrument to set tension on and pull over its hook when installing the key, and furthermore, with many basses the key force has to be set higher than is really comfortable for the player, in order to keep the key from blowing open. One of the many inherent design flaws of the bass clarinet (which IMHO is about due for a major ergonomic redesign --- hear that, Leblanc and Selmer? Hire me and I'll show you what needs to be done.....)
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Author: DezzaG
Date: 2003-08-29 13:51
Dave, please show me, I am interested
dr_grice@yahoo.com.au
I promise to not steal your design, I am interested thats all!
Promise!!!!
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Author: Don Berger
Date: 2003-08-29 14:54
Hi Graham - I'm in complete agreement w: Dezza and Dave re: a stronger spring. Also I'm asking if your B C, like my Selmer, has the alternate [left L F] Ab/Eb lever? You might get a resonance-induced vibration in its "operating linkage" if its not silenced by cork, waxed paper, et al. Now, our weather report! Rain in the mid-America "desert", Okla etc !! Only problem so far was a lightning flash, to someome's power line, knocking off my previous post, TV's etc. Obliviously, it came back, am hurrying!!. Don
Thanx, Mark, Don
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Author: graham
Date: 2003-08-29 15:35
Thanks guys.... the first tech fitted the biggest non-blue steel spring she had, but I suppose it just isn't enough. She said she just couldn't do more. I'll take it back to the second tech and ask him to fit a really mean one. I could handle more stiffness quite easily. What I don't know is whether they have one that is strong enough for the job.
Don, no my bass is out of the ark and has no alternative key, hence no sympathetic vibrations. It is a Chabot.. unique, but troublesome.
Don, you may be amused to hear that a partial power failure in London's "National Grid" brought our underground and overground services to a halt last night, so it doesn't just happen in the US. They fixed the power loss in 20 minutes, but by that time passengers had got out of the trains and were walking on the track, so they couldn't turn the track power on for a further two hours!
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Author: Don Berger
Date: 2003-08-29 16:08
Hi[gh?] G - When I first saw the news about a power failure, in an undefined metropolis, on CNN , my thot was, Gosh, not again in NYC!! Sure isn't good to share problems [electricity AND Iraq], is it? We have visited London frequently, riding the tubes [some DEEP ones!] and buses, to your GOOD train service. Very enjoyable! Back to Bass cl, [Mark], I've seen some leather pads with a loop of thread in the center, presumably to tie it down, maybe to prevent its vibration. Any experience, Dave S ?? Don
Thanx, Mark, Don
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Author: David Spiegelthal ★2017
Date: 2003-08-29 16:37
Don, I don't know about the thread in the center of the pad, sounds like another alternative to rivets or resonators for preventing the center of the pad from sagging. With leather pads (used on every decent bass clarinet except Vitos, for the life of my I can't fathom why Leblanc USA persists in putting bladder pads on their student harmony clarinets) buzzing or vibrations are NOT coming from the pads --- the sources lie elsewhere.
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