 The Oboe BBoard
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Author: HautboisJJ
Date: 2010-02-09 15:35
Greetings fellow bboarders,
I am curious and would like to know more about the mechanism of the half hole system on an english horn. There is an upper plate that covers a pad that contains a hole and 2 adjustment screws connected to both these plates. What effects does one get closing/opening either of those? Which combination is optimum for the speaking of the middle register and the higher?
Thanks!
Howard
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Author: Chris P
Date: 2010-02-09 21:53
If there are two screws fitted, the uppermost adjusting screw controls the opening of the pad (which is connected to the lower/smaller part of the split plate).
A lot of European cors don't have this adjustment fitted and the pad fully opens (the opening is determined by how much venting the upper part of the split plate has). But having the extra adjusting screw fitted to adjust the venting of the LH1 pad will help the lower altissimo and mid C#, D and Eb notes in how they respond and sound.
The adjusting screw fitted to the upper part of the split plate is to further adjust the venting of the diamond aperture (and the venting of the LH1 pad if that doesn't have the extra adjustment fitted), though a lot of cors don't have an adjustment on here - the venting is usually determined by the thickness of the cork glued to the foot.
My Marigaux cor didn't have the extra adjustment for the lower plate/LH1 pad, though I had one fitted so I could lift LH1 off instead of having to roll onto the lower plate. I couldn't get on with it when the top plate was fully opening as I'm used to lifting LH1 off completely for the lower part of the upper register and altissimo.
The way I normally set the split plate on cors for the UK market is to have the upper plate open fully, but the lower plate to barely open at all - just a minimal amount of movement in it (similar manner as the 3rd 8ve key and RH2 fingerplate when lowered by the low C key). On instruments for the European and US market I set the split plate so both parts open fully - the lower plate/LH1 pad venting being determined by the opening of the upper plate.
It's mostly on prestige models of cors that have two adjusting screws for both parts of the split plate mechanism. Most cors have one adjusting screw, either on the top part of the split plate to adjust the venting of both the LH1 pad and top plate, or (as on Howarth cors) to adjust the venting of the LH1 pad only while the top plate opens fully.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: jhoyla
Date: 2010-02-10 06:44
Chris has summed it up masterfully, as usual!
The only other thing I would mention, though it was not asked, is the clearance for the C tone-hole which is governed by the height of the lower-plate when closed. There is no adjusting screw for this.
If you are re-corking either the "half-hole" pad or the bumper cork beneath the lower plate, take the needed clearance into account. If your half-hole pad is too thin or the bumper cork too thick it can seriously muffle C in both registers.
J.
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Author: Chris P
Date: 2010-02-10 10:08
With the lower plate and C key, make sure the LH1 pad is reasonably thick (but still allows the full venting of 2mm if you like it to be fully open) and the C key pad is thin (almost level with the lower edge of the pad cup) so the C key doesn't clatter against the underside of the lower plate.
But most makers will allow for plenty of clearance here - the C tonehole bedplace is usually recessed deeply into the top joint to allow the C key to sit very low beneath the lower plate and still have the proper venting.
If there's enough room (clearance in between the C key and underside of the lower plate) when the lower plate is closed and the C key is open, cover the underside of the lower plate with a piece of thin cork (as thin as you can trim it). Over time the lower plate can bend downwards and this prevents any metal against metal noise that can happen.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: HautboisJJ
Date: 2010-02-13 04:30
Amazing photos Chris!
This has been of utmost help, i have a programme of Petrushka + Daphnis Chloe (YES, on the same concert) coming up soon and also an audition where i have to play the you know what excerpts for cor... I am still trying to find the balance that will allow me to roll my left hand index finger and use short fingerings in the altissimo. And of course at the end of the day there must be a reed that works! Ha!
Howard
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Author: Chris P
Date: 2010-02-13 09:50
What make/model cor are you playing?
You should be fine if you adjust the pad (with the upper adjusting screw) so it barely opens, and the upper plate opens fully. This will allow you to use short fingerings and also let you roll down and lift off LH1 completely.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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