 The Clarinet BBoard
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Author: graham
Date: 2004-01-12 17:00
My bass has some tuning difficulties just above the break, in that it is sharp on the B/C/C sharp. It has a double register key, and I have noticed that, if I allow the register key almost to shut, but not quite, the pitch goes down quite a bit. It seems only to need the merest crack of the bottom register hole open to overblow, but the pitch is better.
So, I am thinking of adjusting corks etc to cause the hole to open only slightly, even when I wack the register key down as hard as always. To do this I will have to allow the upper register hole to open only slightly as well, but from what I can tell, that will not hinder the register above D sharp. This all has to be done quite carefully so that the lower register pad will open as fully as possible when I finger throat B flat, despite only oppening a crack when I want the instrument to overblow.
The point of this discourse is to ask if anyone thinks there is something in this idea that I have overlooked and may prove disadvantageous.
Many thanks
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Author: Don Berger
Date: 2004-01-12 17:45
Graham - 1. Dave S and others [Walter G et al, BC group]] prob. have much more experience than I on B C's in general, D R K s in particular. 2. My best, a Selmer 30's model to Eb, shares its lower reg tonehole [some 3 mm in dia. with pad rise about 1+ mm] with the "pinch" Bb, about 1 1/2 " above the next-to-top trill key [for alt. Bb with A]. This configuration is very similar to that on an old Conn BC, 1940's vintage. SO, what make is your BC and what is its keying structure? 3. When our comm. band tunes to C, concert Bb, I check all 3 C's and several G's and find very little "lipping" needed. 4. I use a Valentino cl pad on the high [neck] R K and a bladder pad on the lower key. 5. It did take me a while to make the DRK work well, but have had little trouble since. Am interested in this thread, obviously!, and in the older and newer [Yamaha] patents on the DRK configurations. Don
Thanx, Mark, Don
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Author: William
Date: 2004-01-12 22:43
I just pull the middle joint of my low C bass about the width of a nickel and that seems to help lower those notes you mentioned, without harming the pitch of the lower register notes, B3 and on down. I'll have to look into the resiger key idea, however. Perhaps a trip to see Walter..............
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Author: graham
Date: 2004-01-13 09:21
Thanks for these points. I have tried a bit of pulling out and other such things but with only marginal success.
Don, the instrument may well be the sort of age you mention. It is an Andre Chabot made in Paris, and my guess is 1930s/40s. The lower register hole also does service for the throat B flat, and I need it as wide open as possible for that particular note. I have had the tuning issue for years, and have only just realised that by reducing (drastically) the clearance of the lower register hole the bell notes flatten. This hole is almost dead in line with the top most side trill key. I have no measuring equipment with me but a diameter of 3 mm looks likely, with clearance of about 1/2 mm.
Yes I hope DS may make some comment!
Thanks
Graham
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Author: David Spiegelthal ★2017
Date: 2004-01-13 12:51
Graham,
I'm so flattered by your 'request for comment' that I feel I should comment......if your methods work, then by all means go ahead with your plan, but be advised that the good results thus obtained will be extremely sensitive to the register key heights and will change as corks wear and/or the instrument gets knocked about. The sharp lower-clarion B/C problem is extremely common with (I'd say 'endemic to') older bass clarinets (and also to current Leblanc products which are essentially an old design they've never taken the trouble to improve!), thus my preferred permanent fix has been rather more invasive: I extend the lower joint lower tenon by about 1/4 inch or more, line the top half of the inner rim of some of the lower toneholes and may even extend the lower half of the lower toneholes toward the bell, to shift them downward, all to lower the pitch of those offending notes --- the downside is that the low chalumeau notes are flattened in pitch also, but only by about half the amount the clarion notes are brought down. I find it to be a workable compromise, but clearly it's not a job for the amateur! Best of luck to you.
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Author: Grabnerwg
Date: 2004-01-18 19:08
Sharpness problems are endemic on the long "B" and "C" on many models of bass clarinet. There are as many different solutions as there are different makes and models.
The problem of course, is exacerbated by the fact that the low F and E and almost always flat, often unacceptably so. So anything you do to the B and C need to take this into account.
The problem is that the 12ths are just too wide. This is caused by placement of the register vent(s) and/or bore configuration, both of which are very difficult to correct.
Inserts in the toneholes can help, but only if that doesn't lower the E and F too much. Sometimes, adjusting the register key pad so it barely opens can help as well. That sometimes can cause a hissing sound.
I have also heard of vent key(s) operated by the thumb, which help the low E and F.
One thing I have done in the past is to add an "extension" to the bass clarinet. If you examine a low Eb bass, you will see that the B and the low E are vented through the tone hole on the bell. Often times, that tone hole is "the wrong size" or positioned incorrectly. I made a low "D" extension for a bass clarinet a year or so ago, which involved making a section of wood or delrin and cutting a new tone hole for the E/B. This really helped the tone and the tuning of those notes. However, this is very time consuming and therefore very costly.
Walter Grabner
www.clarinetxpress.com
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Author: Wes
Date: 2004-01-19 04:22
These tuning situations on older bass clarinets tend to make people buy the newer more in tune instruments rather than struggle with the notes.
In my H. Lefebre bass clarinet, there are two register holes, one for the Bb and the other for the rest of the clarinet. There is no register key opening with the third finger of the R hand as on most new bass clarinets and also on the Bundy contra alto. It has to do with the instrument bore and how much undercutting is done.
On mine, the undercutting is quite extreme, a very labor intensive process on a bass clarinet. You may recall that undercutting a tone hole will raise the lower register and not the second register. Thus the tuning on mine is quite good, except that the middle B is a little high and the low E is about ok because these are vented by a metal non-undercut tone hole. To fix this, one can fashion a special tapered filler for the metal tone hole that makes it like an undercut tone hole. This leaves the low Eb which is ok but the generally-unused long middle Bb is sharp which is also ok. It's an interesting subject! Good luck!
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