Vibrational mode shapes in Caribbean steelpans. I. Tenor and double second

Vibrational mode shapes have been studied in several tenor (soprano range) and double-second (alto range) steelpans by three well-known makers. Normal modes are determined from operating deflection shapes recorded by means of electronic TV holography. Vibrational modes of the various note areas are designated by the number of radial and circumferential nodal lines. Tuners generally tune one mode an octave above the fundamental and, if possible, a third mode is tuned either a twelfth or two octaves above the fundamental. Note dimensions follow an approximate scaling law L=Kf(213), and the larger note areas can be roughly modeled as rectangular plates with simply supported edges. Modal shapes in the skirt correspond to standing bending waves propagating around the ring.