Experiments with a digital bow
Gabriel Weinrich, René Caussé · The Journal of the Acoustical Society of America · 1984
Relatively few direct experiments on the bow-string interaction have been done in the past because the exact velocity dependence of the bow force is very difficult to measure, let alone control. We are attacking this problem by constructing a computer-operated “equivalent bow.” The bowing point of a (metal) string is placed in a strong localized magnetic field, so that an electric current passing through the string gives rise to a force applied at that point. This current is, in turn, controlled in real time by a computer making its decisions on the basis of the instantaneous velocity of the string, as measured by the digitized output of an appropriate sensor. By programming the function that relates the current to the velocity of the string, we in effect control the equivalent frictional characteristic of the bow-string interaction. More complex dynamical models can also be realized. [Work supported in part by NSF.]