Playability of the wolf note of bowed string instruments

Playability is an important aspect of the evaluation of bowed string instruments. The well-known “wolf note” of a cello is a particularly obvious playability issue, and it has been suggested that susceptibility to wolfiness might be deduced directly from a measurement of the Schelleng minimum bow force for the playing of a steady note. This prediction is explored by comparing physical measurements with the experience of players after making controlled mechanical changes to a cello. Experienced luthiers and musicians made subjective judgements of changes in the severity of the wolf note, under blinded conditions. The results strongly suggest a direct and intimate link between the measurable acoustical parameter and perceptual discrimination. This simple acoustical measurement can help instrument makers to identify problem notes, and to assess the effectiveness of different possible interventions.