KEYBOARDS V: Key Balancing
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|An indiscriminately weighted harpsichord keyboard|
About balancing the keyboards…
Harpsichord keys should not have to rely on the jacks to push their tails down when released. Each key by its very nature has different mass, with variation front and back of its determined pivot point. Working on the keyboard out of the instrument, some makers are particularly careful balancing each key to the same mass to ensure uniformity of touch. This can be done by under carving the keylever, or in certain cases, adding lead.
Sometimes makers just lazily add a lead slug at exactly the same point near the tail of each key. While this might ensure every key returns, this balancing method pays no attention to the unique quality of each key and is detrimental to the touch: A sensitive player can immediately detect keys which are heavier or lighter than the norm.
It’s far better and doesn’t take much longer to balance a keyboard properly. Refer to our video below to see how this can be done.
With time, the lead used for balancing can corrode, expand and interfere with adjoining keys. This is a common cause of keys becoming sluggish and eventually sticking, and is discussed in the Tropics section. In bad instances, the wood of the keylevers can split and require extensive repair. To avoid these problems, we use a special corrosion-resistant lead alloy made for stained glass work.
Timothy Murray demonstrating how to balance a French Double Harpsichord lower manual key.
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