Spectral Frequency and Overtone Analysis of Javanese Gamelan in Slendro Tuning Using Digital Signal Processing (DSP)

Abstract

Javanese Gamelan is a traditional Indonesian musical ensemble recognized for its distinctive spectral frequency distribution and inharmonic overtone structures. Unlike Western tempered instruments, Gamelan employs a non-standardized tuning system where pitch intervals vary based on tradition and craftsmanship. This study analyzes the spectral frequencies and overtone characteristics of key Javanese gamelan instruments in the Slendro tuning system, including the Saron, Bonang, Gender, and Gong Ageng, using Digital Signal Processing (DSP) techniques. The data were collected from direct recordings and processed using Fast Fourier Transform (FFT) with optimized windowing functions to minimize spectral leakage. The results reveal that each instrument exhibits unique spectral signatures, with varying degrees of inharmonicity. For example, the FFT analysis of the Saron demonstrates a fundamental frequency of approximately 430 Hz, with overtones at 860 Hz, 1290 Hz, and 1720 Hz, deviating from the harmonic integer multiples found in Western instruments. Similarly, the Gong Ageng exhibits a dominant low-frequency resonance, contributing to its deep and sustaining tonal quality. Furthermore, variations in playing techniques significantly affect overtone distributions, influencing the timbral characteristics of each instrument. These findings provide valuable insights for digital gamelan synthesis, acoustic modeling, and cultural preservation through computational techniques, ensuring an accurate representation of gamelan’s unique sonic properties in digital formats.