Wolf Tones and Humidity in Violins

This paper attempts to, perhaps for the first time in this type of studies, quantitatively evaluate the severeness (as defined in this paper) of the undesired wolf tones on a violin as the surrounding humidity changes. The severity of the wolf tones was evaluated by a skilled violinist under various humidity conditions. It was found that a total duration and frequency of occurrence of wolf tones during a set period time are largest around 50% humidity, a humidity at which violins are recommended to be maintained for optimizing the projection across the entire register of the instrument, whereas other characteristics of the wolf tones, such as modulation index and the period, did not exhibit significant changes over the humidity change. When the humidity deviates from 50%, the total durations and the occurrence frequency of the wolf tones both diminishes. On the other hand, the amplitude (i.e. volume) of the wolf tones are larger on the lower humidity and the higher humidity ends, and was smallest around 50% humidity. These findings may shed new light on the traditional theories and analysis of wolf tones as well as on evaluations of various wolf tones elimination methodologies. It was also found that although the evaluation method involved some subjectivity, this way of evaluating the wolf tones had consistency and a good degree of reliability, paving a new way to quantify the wolf tones.