Bowed String Instruments

This chapter focuses on the interaction between a bow and a string, and on the resulting self-sustained oscillations. It starts with the presentation of the friction phenomena and tribology of the rosin, which play a major role in the dynamics of the bowed string. Among the variety of possible dynamical regimes induced by the stick-slip mechanism on a string, the so-called Helmholtz motion (HM) deserves particular attention because it is the most widely used in the musical context. First, the kinematical and dynamical characteristics of the ideal HM are described. It is followed by the presentation of some more realistic features of the HM observed on real strings, such as the flattening effect, the wolf note, and the anomalous low frequency (ALF) tones.