Plate Vibration of Stringed Instruments at the Wolfnote

The wolfnote observed frequently in cellos near F♯ on the D string (about 190 c.p.s.) is characterized by high emission of sound energy from the instrument with a rapid cyclical variation in intensity. The tone produced by the instrument is hard for the player to control and unpleasant in character. According to Raman, two modes of string vibration exist in this case. Because of rapid dissipation of energy from the string at this frequency, the string alternates between the two modes, with a resultant cyclical variation in the intensity of the sound produced by the instrument. The high energy dissipation from the string at this frequency is associated with particularly strong radiation from the instrument, as shown by a distinct peak in cello response curves. A comparable response peak occurs in the same relative part of the compass of violins and violas. In all three instruments, the wolfnote peak is the first marked peak above the main air body resonance, and lies in the range where the belly of the instrument is the principal radiating element. The work reported here identifies the principal mode of plate vibration at the wolfnote frequency. This same mode was observed on a number of violins, violas, and cellos; it was also observed under a variety of conditions on a flat brass plate shaped like a violin. A number of plate modes are illustrated by means of Chladni sand figures, and the influence of the bass‐bar and soundpost on normal plate modes is discussed. Several methods of reducing the strength of the wolfnote are mentioned.