Experiments on the bowed string are often carried out on monochord setups [1] and with
specialized bowing machines [2, 3, 4, 5] in order to study the excitation in detail. These setups
simplify the equipment with the necessary sensors. Furthermore, by using rigid body monochords,
measurement uncertainties can be minimized by eliminating vibrating components such as the
resonating body, bridge, neck, etc. When the string is then excited or bowed using a machine,
there are further advantages in terms of reproducibility or controllability of the excitation and
bowing parameters.
This technical report provides technical details of a monochord built at the acoustic laboratory
of the Department of Music Acoustics – Wiener Klangstil (IWK). The advantages of using strain
gauge sensors for string vibration analysis are presented and discussed. In contrast to a custom-
made bowing machine, however, an industrial robotic arm was used for string excitation, thereby
allowing for highly versatile applications. Enclosed detail pictures, circuit diagrams and software
flowcharts provide the possibility of simple replication of the setup described.