Vibrational characteristics of Saron Barong metallophones in the 1893 Field Museum Gamelan

Abstract

The gongs used in Asiatic music frequently exhibit noticeable glides in pitch comprising a significant fraction of a semitone. Bar-form metallophones of the 1893 Gamelan also show a glide in pitch. This contrasts with western bar-form metallophones which are generally pitch stable. Measurements of the keys of two Saron Barong show that they have different lengths, widths, and cross sections but do not “scale” since they have nearly similar masses. The keys of lower pitch are longer and wider than those of higher pitch within a given seven note Saron. The upper surface of the keys is convex for both length and width aspects. The lower surface of the lower pitch keys is concave becoming convex for the upper keys. They are mounted with nails through holes at a distance one quarter the length from the end on resilient pads above individual air cavities. The holes are not symmetrically located and the bars are not straight. They were cast of bell metal in sand molds and roughly finished. The central part of the underside is hollowed. Torsional and flexural modes near the pitch frequency can be found by external excitation. These modes have frequencies consistent with those found by high-speed spectral analysis and pitch measurements. The pitch glide seems to be associated with a bar shape that favors excitation of both torsional and flexural modes at the initial strike with a more rapid decay of the torsional mode. This mechanism differs from that suggested for gongs where the moving mass associated with the mode decreases with decreasing amplitude of vibration.

Comparative acoustical and psychoacoustical analyses of gamelan instrument tones.

“…The brevity of the inharmonic com ponents is another aspect which could contribute even more to the saliency of the fundamental. All gamelan bars which we have examined have a similar time-variant spectral trajectory, like those of the Chicago Field Museum of Natural History 1893 gamelan (Savage, Kottick, and DeVale, 1979). Figure 6 shows a single analysis frame from near the beginning of the tone.…”

Vibrational characteristics of Balinese gamelan metallophones

“…6 ) Other researchers have made some observations of the vibrational characteristics of gamelan metallophones, but most of these address either the properties of Javanese instruments, which do not have trapezoidal bars, or some aspect of the sound other than the vibrations of the bars themselves. 3,[7][8][9] In this Letter, we describe the vibrational characteristics of the Balinese gamelan metallophones and compare them to those of the glockenspiel.…”