The spectral and temporal description of Javanese Gong Kempul

In Central Java, the Gong Kempul is one of eminent gamelan instrument, an ensemble of predominantly struck instruments found across Central Java and has deep philosophical meaning for Javanese. However, there lack of studies concerning on this particular instrument as a bridging means between scientific description and human artistic perception. This study aims to investigate the spectral and temporal properties as well as particularly look into the typical wave-like sound of the Gong Kempul. Acoustic measurements were conducted and analyzed using ARTA. Both frequency and time domain analyses were explored to better understand the nature of the Gong Kempul. It was found that the partials at 93.8 Hz, 187.5 Hz, 281.3 Hz, and 375 Hz are the strict integer multiples of the fundamental frequency. It can also be inferred that the fundamental frequency at 93.8 Hz decays much more slowly than the other harmonic. In addition, the pitch of the Gong Kempul slide upward as the time goes on. The wave-like sound of the Gong Kempul is due to the beat phenomenon between two partials that occur closely.