Sorbonne Université, CNRS, Institut Jean Le Rond d'Alembert
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.
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