Measuring Violin Bow Force During Performance

Abstract

Violin bowing is a complex skill and controls a majority of the sound produced by the instrument. Yet despite significant interest in the modal analysis of violins, comparatively little work has been done to study the complexities of this “input.” In this work, we have used fiber optic strain sensors, a modern strain sensing technology, to test a novel method for measuring bowing force during violin performance. Gaining greater insight into how violinists vary bowing force to create sound could not only lead to better violin excitation methods for modal analysis but might also key in discovering indicators of violin quality and musician preferences. Live performance testing was performed by a professional violinist on two violins of differing quality and at different volume levels. The results showed a log-linear relation between bowing force and volume. In addition, a bowing gesture named the “average down-up stroke” was found by averaging several similar gestures. Its duration was observably longer for a high quality violin compared to a fair quality sibling. Such a measure could be adapted for various gestures and styles and subsequently be explored as a potential indicator of violin quality or player preference.