An extended geometric model for analysis of string crossings in bowed-string instrument performance

Erwin Schoonderwaldt , Matthias Demoucron

In earlier motion capture studies of fast repetitive bowing patterns across two and three strings it was shown that string crossings were consistently timed earlier than bow reversals. This behavior might have a plausible acoustic explanation: a good attack on the new string requires that bow force is built up before acceleration can take place. An earlier used geometric model of the bow and the violin fails to adequately describe the transfer of bow force between strings because it considers string positions and bow inclination transition angles between strings to be fixed. A new geometric model is proposed that (1) takes the compliance of the strings and the bow hair explicitly into account, and (2) includes a correction of string crossing angles for stopped strings. The model requires knowledge of the tensions of the strings and the bow hair, as well as the depth of the fingerboard below the strings. It will be shown how these quantities can be obtained by a simple calibration procedure. The model allows for an accurate calculation of control parameters to drive a virtual violin, allowing to study the relation between bowing movements and the quality of attacks in complex bowing patterns.

Mots clés: violin bowing; motion capture; bow force; music performance

Domaines: Acoustique [physics.class-ph]

Erwin Schoonderwaldt, Matthias Demoucron. An extended geometric model for analysis of string crossings in bowed-string instrument performance. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00811209⟩