The wolf in the cello

The occurrence of the wolfnote in the cello is shown by direct tonal analysis to be caused by the beating of two equally forced oscillations. The fundamental sinusoidal component of vibration of the string is shown to split at the wolfnote into a pair of oscillations separated by a frequency interval equal to that of the stuttering frequency of the wolfnote. In one of the two cellos investigated, higher partials up to the third are also split into pairs, their separation being the multiple of the harmonic number and the separation of the fundamental pair. Further evidence is obtained to support the interpretation of the wolf as beating between two equal forced vibrations from a frequency analysis of the bowed-string vibration for different stopped string lengths. The frequencies of vibration of the string bear a close resemblance to those obtained in coupled electrical resonant circuits.