Setting up a clavichord
(This is a shortened version of Workshop News, March 2004)
I have not been idle since my last report: I have completed one clavichord and am working on another one. Both are versions of the small 'German' fretted clavichord. I shall shortly begin setting up the second one to play.
Setting up a clavichord is a surprisingly complex process; it calls for quite large amounts of time, as well as skill and judgment acquired through experience. Yet unless it is done well, a clavichord can all too easily be disappointing in performance. There must be many instruments which could give much more pleasure to their owners than they currently do, if only they were set up with sufficient care.
Setting up involves repeatedly pulling yourself up by your bootstraps. Let me try and describe the process:
- The first stage is to make sure that the keylevers all move freely, and that they all fall back without catching on the guide or adjacent keys. Later on, the balance of the keys will be adjusted again to achieve a smoothly progressing fall-back weight, but at this stage all thats needed is to make them fall back reliably.
- Next I put on the strings, choosing the gauges on the basis of previous experience with the same model: this may or may not need changing in due course.
- Then I put in some temporary listing, just enough to damp the left-hand ends of the strings so that the instrument can be tuned using the keys and tangents. On a fretted clavichord like this one, I measure the distance between any two tangents which strike a single course and, if necessary, correct it by bending one or both of them to the left or right.
- The strings are then chipped or roughly tuned to their correct pitch. There is no point at this stage in attempting any fine tuning, because the strings will go out again within a few minutes as the structure of the clavichord adapts to being under tension and the wires stretch. The instrument is then left for as long as possible (at least a week), and chipped up from time to time until it reaches the point where an accurate tuning is possible.
- Now the fun really begins. I adjust the height of the tangents so that the keys go down roughly the same distance at the front, aiming for something less than the final contact distance. With traditional blade tangents its easy to reduce the height by taking material off, but much harder to increase it, so I aim on the safe side! As well as the height, I adjust the angle of the tangent-tops so that the back string of each pair is struck an instant before the front string. This is perhaps the most crucial single adjustment in the setting-up process: the interval must be very small, almost imperceptible to the unaided eye (so I have to use a magnifier) otherwise the sound will be weak; but without this tiny separation the sound will be blunt and coarse, without sustain. So, as I go, I have to listen to each note and compare.
- Now I listen to the sound of the instrument. Coarse, barking notes can be rendered more civilised by adding mass to the keylever near to the tangent. Weak, whiny ones may need to be strung one gauge heavier. More adjustments may be needed to the angle of impact. Perhaps the tangent-top is too wide and needs to be filed either side to make it narrower. An attempt must be made to put in the final listing: this I do starting at the bass, trying to ensure that damping is adequate but also that there is no more listing than absolutely necessary. I use a woven listing because it helps to even out the hardness of the bottom of the touch.
- After continuous listening and cycles of adjustment, when I am sure that there is not much more improvement to be made, I balance the keys to achieve an even fall-back weight, adding weight to the rear of the keylevers or to the front, as necessary, or carving away underneath the key heads. I need to bear in mind that mass added to the lever near the tangent will affect the sound - usually for the better.
- Ideally the process should continue for about 12 months, but generally thats not possible and the clavichord has, finally, to leave my workshop. I try to live up to John Ruskin's dictum:
No artist must ever allow to pass from his hands a work which his further diligence might improve.
The clavichord which is the subject of all this care has been fitted with twined strings, made as described in my previous bulletin, on the three notes of the short octave (C, D and E). I can report that they are a big success: there is hardly any audible transition from the twined notes to those strung in plain wire, which in view of the large change in scale between E and F is remarkable. The twined strings are also much easier to tune than the plain wire strings I fitted in this position on a previous instrument of the same type. I have done some bench-top experiments on the behaviour of twined strings, the results of which I am still analysing.
Meanwhile, I have begun work on a little book on Tuning and Maintenance of the Clavichord, based on my series of articles in the British Clavichord Society Newsletter. [This book has now (2007) been published by Keyword Press].
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