The bowed string

The complex function of musical instruments has traditionally fascinated scientists and engineers. This resulted in a field of study, namely Music Acoustics, where sound generation by musical instruments is one of the main subjects. In this project the focus lies on the bowed string. The interaction between a bow held by a musician and the string of a bowed-string instruments (such as a violin, viola or cello) also taking into account any feedback from the instrument`s body, has been under investigation over the past decades. However, there are still open questions regarding how the bow is causing the motion of the string. This is eventually transferred to the wooden body of the instrument, which is set into vibration and radiates sound in the surrounding area. In order to shed more light into this interaction, experiments will be carried out in three main categories: (i) the performance of real musicians will be analysed using sensor technology that can capture their actions (similar to motion-capture technology used for animating digital character models in computer animation); (ii) a robot arm will be instructed to perform in a similar manner to human musicians. This allows to run experiments for longer durations while ensuring that the robot is always performing in exactly the same way, something that is impossible in practise for human players; (iii) information gathered by both types of measurement approaches will be used in order to develop a computer algorithm that, based on physics principles, will be able to generate synthetic sounds similar to those performed by the musicians. Having a so-called physical model of a musical instrument that takes the actions of the performer into account and has been validated via experimental measurements, allows to systematically study the effect of every part of the system (in this case the player-bow-string-instrument system) on the generated sound. This can be achieved, since in a computer simulation the user may change only one system parameter (e.g. the velocity of the bow) while keeping everything else constant, in order to assess the effect of that single parameter. Such a systematic study is extremely difficult, if not impossible in real experiments, because changing a system parameter usually also affects other parameters. The findings of this study, besides enhancing our understanding of the function of bowed-string instruments, may also provide students and teachers with illustrative examples of sounds that result from specific bowing actions, could yields results that are of interest to instrument makers regarding the role of certain instrument parts and will also generate valuable research tools for future studies in Music Acoustics. Finally, the resulting algorithms may be used for sound synthesis applications within contemporary electroacoustic composition and sound design.