Sorbonne Université, CNRS, Institut Jean Le Rond d'Alembert
Abstract :
The clavichord is considered to be the most demanding
keyboard instrument in terms of finger control. This is because of
its direct mechanisms: the key works as a lever. When the finger
presses the key, the tangent (metal rod) on the key’s extremity
goes up and strike the string. And as long as the finger remains
pressed on the key, the tangent remains in contact with the
string, leading to string's tone variation. The loudness of the
sound is proportional to the velocity of the key’s displacement.
Then there is a duality between loudness and pitch accuracy.
This is the paradox of the clavichord. The objective of the study
is to analyze experimentally the sounding consequences of the
instrument with respect to the gestural strategies of the finger. To
proceed, we use a robotic finger that can simulate different
trajectories, either ideal trajectories (e.g. vertical or sliding
motions) or actual trajectories performed by clavichord players.
Players’ trajectories are extracted by image processing of films
made by a high-speed camera. Vibratory and acoustical
measurements are performed, upon which relevant indicators
are used to compare different configurations. The finger
performing a circular motion reaches a good compromise
between tone and loudness.