Collin, Samantha; Keefer, Chloe and Moore, ThomasProceedings of the Third Vienna Talk on Music Acoustics (2015), pp. 120–123
The Himalayan singing bowl is a nearly symmetric metal bowl that produces a musical sound by rotating a wooden stick around the outside rim. The wooden stick, referred to as a puja, excites vibrations through a stick-slip mechanism. The amplitude of vibration is directly related to the applied force and velocity of the puja as it moves around the bowl. Typically only a single vibrational mode is excited, resulting in narrow-band oscillation at a frequency determined by the size of the bowl. However, as the angular velocity of the puja increases and/or the force of the puja on the bowl decreases, an audible chatter will often occur. The goal of the work reported here is to determine the origin of this chatter. Initial results indicate that the puja does not lie directly on a node of the radiating mode. Furthermore, the position of the node with respect to the puja changes as a function of rotational velocity. Because the puja does not lie directly on a node, it appears that as the amplitude of the radiating mode is increased the puja can lose contact with the bowl resulting in a chattering sound.