Musical Acoustics of Water CrotalesRandy Worland
Orchestral crotales are small bronze cymbals shaped like disks with an added central mass. Each crotale produces a definite pitch when struck with a mallet, with a typical set encompassing two chromatic octaves, from C6 to C8. Contemporary composers writing for percussion often incorporate unconventional playing techniques with the use of traditional instruments. Among these extended techniques is the lowering of gongs and crotales into water as they are being struck, resulting in a glissando effect that involves changes in both pitch and timbre. The orchestral crotale has a relatively simple geometry and overtone structure, making it an appropriate starting point for the study of this performance technique. Results of an experimental investigation of crotale vibrational modes in water are presented, along with a simple effective mass model describing the various observed effects. Mode frequencies, shapes, and degeneracies are investigated as a function of water depth using electronic speckle-pattern interferometry.