Dynamics of the Himalayan singing bowl

Abstract

The singing bowl, commonly known as the Tibetan or Himalayan singing bowl, is an idiophone indigenous to many Asian cultures. Singing bowls are usually made of brass, which is hammered into a nearly symmetrical hemispherical shell and then hand-turned on a lathe. A sound is produced by either striking the bowl or rubbing the surface with an excitation stick referred to as a puja. We report on an investigation of the sound generation mechanism of the singing bowl, with an emphasis on understanding the origin of the sound created by the stick-slip excitation mechanism that occurs while rubbing the bowl with the puja. It is shown that both the radial and tangential motion of the puja experience exponential gain during the excitation process, and the feedback mechanism required to produce this behavior is discussed. A slow oscillation in the sound produced by the bowl is explained by the dominance of a single vibrational mode that rotates at the angular speed of the puja.