EFFECT OF HUMIDITY ON THE MEMBRANE VIBRATION OF MUSICAL INSTRUMENT KOMPANG

This paper presents the effect of humidity on the goat skin membrane of traditional musical instrument kompang. Three kompang samples with similar size of 25 cm diameter were exposed to three different relative humidity (RH) conditions (50% RH, 70% RH and 90% RH) under the Climate Chamber. The tension and the vibration frequency were measured every 8 hours in anechoic enclosure. It is found that after 48 hours of humidity exposure, the tension of the membrane reduced by 6.2% for 50% RH, 13.1% for 70% RH and 21.5% for 90% RH. The frequency of the sound produced by the membrane also lowered by 4.6% for 50% RH, 18.7% for 70% RH and 26.4% for 90% RH. The goatskin membrane is sensitive to the humidity so that the sound changes to lower frequency as the humidity increases. The lowering frequency is due to the tension lost of the goatskin membrane.