Sorog and Pelog Scales in the Vocal and Rebab of Sundanese Gamelan Salendro

This study aims to analyse and explain the unique phenomenon of Sundanese gamelan salendro performances in West Java, Indonesia, that is the fixed pitch instruments of gamelan are in the salendro scale (laras salendro), but its vocal and rebab (a two-stringed fiddle) conventionally modulate into sorog scale (laras sorog), and occasionally into pelog scale (laras pelog). The study of this phenomenon at the same time serves as a review of Kusumadinata’s scale theory which has been taught in educational institutions, stating that “sorog and pelog are the scales derived from salendro (gamelan salendro)”. To analyse this phenomenon, the actual performances of various pieces of gamelan salendro, especially rebab, were examined. Based on the results of the analysis, it is explained that there are four types of sorog occur in the gamelan salendro performances; two of the four types appear most frequently, and in a long piece, three or all four types may appear. The results of this study indicate that pelog is not a scale derived from salendro, but sorog is presumed as a scale derived from salendro by this phenomenon. As to when this phenomenon took place, it would require further research with historical approaches.