A decent instrument originates from a well dried, selected wood. The most important part - a soundboard - is made from spruce from the Alps or from the Bohemian forest. Each emitting area require a different stuff: for bass, middle and diskant are used planks with appropriate quality.
A thickness of the soundboard is an often discussed topic. It is necessary to divide the board into regions with a different thickness ranging usually from 4,2 to 1,8 mm. This is done taking into account a bridge position, a distance to the instrument's edge or ribs etc. However, it shouldn't be overestimated, regarding a sound quality and power. The soundboard is supported by underside ribs that have more significant influence over the sound - according to my experience at least. Even a well designed board has to be finally adjusted (regarding board thicknessing and modification of ribs). This difficult task precedes tapping and bending, checking a correct stiffness.
Case preparation is equally important. Its role is on the one hand to give a sufficient space for the soundboard (for example by cutting-out the bearing surface of the liner in the diskant area), on the other hand it has to be rigid enough to permit the soundboard to vibrate. This issue can be described when comparing thin-sided Italian harpsichords and late heavy instruments. A case with thick sides supports the soundboard well, allowing long vibrations without damping. Thin sides co-vibrate with the soundboard and take some energy away from it. Of course when designing an Italian instrument this is no mistake - it results in an explosive attack and a fast sound decay.
Hot skin glue, Titebond and other suitable adhesives are used. The soundboard is usually treated with thin layer of shellac. The case is either painted or treated with shellac or oil and wax.
Not only a decent sound makes a listener happy. Correct tuning is needed as well, and unfortunately a wooden case and metal strings react to temperature and humidity changes differently. Beeing a harpsichord player I know this can be tricky, especially just before a concert, people are coming, talking and moving chairs. Output of my years of development in this area are besides the special tuning device (The Listener) these improvements:
- a short distance from tuning pins to the bridge, strings are kept under a correct angle;
- use of polished stainless pins with a good diameter, helping minimize a chance of a string breakage;
- the wrestplank is slightly elevated decreasing a torsion deformation of tuning pins.
As a revolutionary device could be considered - The Listener. A microphone hidden under the soundboard sends sound waves to a transmitter. Tuner takes a cordless phones, receiving harpsichord sounds from the transmitter, and is able to tune the instrument effortlessly. Closed lid and phones help even to filter surrounding noise.
The Listener can be equipped with 16 historical temperaments. The device generates a reference pitch the corresponding tone is than tuned to (using interference method). Very easy and accurate.
Plectra material can be chosen between Celcon, Delrin or bird's quills. Most of my instruments are fitted with Celcon, it has a warm, pleasant sound and is easy to cut. Bird's quill has better sound and overall touch, but needs a bit more care and is more difficult to voice.
Quality strings from Malcolm Rose made using traditional methods help to show the full instrument's potential. There is a certain (a few months) time period for letting strings to develop their sound quality in full.
Wooden jacks from pear or maple, with a boxwood tongue, have a bottom adjusting screws. These screws are on my opinion best becouse:
- there are wide enough to have a good contact with a keylever and make no harm to the felt;
- thanks to its oblong shape and width permit a transposition without a necessity of taking any of the jacks out;
- they are necessary for precise voicing.
A real hog's bristle as a tongue spring is set individually for each jack.
Keylevers are well balanced for maximal responsivness and optimal touch. Some instruments (Cembalino) have a gradual change of balance point location in the bass area to improve the repetition.
Most stands are screwable to the harpsichord bottom to make the instrument moving easier and safer.