Author: Ken Shaw ★2017
Date: 2010-06-18 15:18
moolatte -
It's 99% certain that the register mechanism is out of adjustment.
There are three vents: the upper register vent on the neck, the lower register vent near the top of the upper joint, and the throat Bb vent, lower down. They're controlled by three springs with different tensions, so that one spring overcomes another, plus several levers. Any change in the springs, or crud or lack of lubrication, can throw the balance off.
It should operate as follows:
When you press the throat A key and the register key, the Bb vent should open and the other two should stay closed.
When the throat A key is closed and the right ring finger is down, the lower register vent should open and the other two should stay closed.
When the throat A key is closed and the right ring finger is up, the upper register vent should open and the other two should stay closed.
When the spring tension gets off, or the mechanism binds, one of the vents that should be closed raises or sticks slightly open, which ruins the high register response. You can often see what's happening. Finger throat A and press the register slowly. If either of the register vents moves even slightly, it's leaking. Then finger clarion D and slowly raise and lower your right ring finger. The Bb vent should stay closed and the register vents should alternate, with each one closing completely.
On contras, the three-way action is the very devil to balance. I'd advise taking it to a repair shop rather than trying it yourself, since it probably needs to be taken apart and thoroughly cleaned and lubricated. Also, a contra needs to be handled like a baby. If you so much as bump it against a stand or let the bell bounce off the floor, it can get thrown out. Since this is a school instrument, it's not surprising that it's had abuse and is out of adjustment.
Ken Shaw
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The Clarinet BBoard
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