Behavior of real violin strings, mechanically bowed

Abstract

Traditional methods of evaluating various types of strings for bowed instruments have relied almost exclusively on subjective impressions of expert players. In the real world, busy professionals rarely have enough time or objectivity to provide string designers and manufacturers with precise information. Furthermore, such opinions are affected by factors unrelated to the stings themselves, and are subject to change in ways that are often difficult to relate to the design details of the product being tested. The use of a well-designed bowing machine makes it possible to amass quantities of data on specific strings, enabling string makers to discover the characteristics that are favored by professional artists. Data is obtained for strings having cores of gut, synthetic polymers, monofilament, and stranded steel. By varying bow force, velocity, and distance from the bridge an envelope of usable combinations is accurately determined. Time for development of Helmholtz waveform partial by partial, average frequency variation as well as cycle-by-cycle period variation, and overall spectral distribution can all be determined with good repeatability. Driving strings magnetically instead of by bowing permits frequency determination of individual partials, an indication of string flexibility or lack of it. This work has led to new string designs, incorporating new materials and manufacturing processes.