Acoustic properties of Temen and Wulung bamboo as a Material for Gambang: Sundanese traditional musical instrument

Abstract

Wulung bamboo (Gigantochloa atroviolacea Widjaja) and Temen bamboo (Gigantochloa atter) are common materials for making Sundanese traditional music like Gambang in West java. From subjective judgment of the maker like Mr. Handiman Diratmasasmita, it is perceived that Temen bamboo is more musical and softer than Wulung bamboo when the Gambang are played. Hence, it is instructive to investigate further in order to find the acoustic parameters of both the bamboos that associate with the differences. To deal with the problem, a series of measurements were carried out in ITB anechoic chamber. Two similar-tuned rattle tube from each bamboo are considered in this work. To capture all required acoustical data, a microphone was positioned behind the opening of the rattle tubes. The sounds of two bamboos are excited by impact hammer and the Frequency Response Function (FRF) obtained by spectrum analyzer system. The results are then analyzed and discussed by considering two frequency ranges namely low-mid frequencies and high frequencies. For lowmid frequency range, it is found that the overtones ratio are not much different for example f, 2.4 f, 3.4 f, 4.9 f, 6.9 f are present for the Wulung bamboo while f, 2.2 f, 2.76 f, 4.82 f, 7.02 f exist in the Temen bamboo where f of 527.3 Hz is fundamental frequency or pitch. However, the overall fundamental and harmonics amplitude of Temen bamboo are higher than Wulung bamboo. At high frequency range the amplitudes of the Wulung bamboo are significantly higher than the Temen bamboo particularly for frequencies above 10 kHz. These results can be attributed to a more musical softer sound of the Temen bamboo.