Analysis of bow-change strategies
Knut Guettler · The Journal of the Acoustical Society of America · 2013
One of the most important skills of the accomplished bowed-string player is the smooth bow change. Smooth changes are often necessary in order to keep a phrase flowing, and equally important in situations where the bow is too short for the duration of the given note, the latter requiring a bow change of least possible audibility. The problem arises from the fact that a change of bowing direction requires the rotation of the Helmholtz corner to be reversed, and the phases of the string-velocity frequency components thus to be shifted 180̊. In between the two states, there exists no transition that can fully maintain the sound flow without introducing undesirable noises. However, by choosing the right bowing strategy and gesture, the tradeoff between transition time and noise content can be optimized for the purpose. In practice, different players solve this problem in a number of ways. The present study, which is mainly based on numeric simulations, analyzes the sounding outcome of a variety of possible bowing parameters.