An Analysis of a Gamelan Slendro Tuning



The tuning of Gamelan music has been poorly understood, obstructed by cultural barriers and practical difficulties. Using a few recordings of Gamelan instruments, sampled from the Javanese Gamelan ensemble at Arizona State University, we determine the frequencies of a Gamelan musical scale, and then compare whether and equal tempered scale or a just intoned scale better explain the musical intervals. We find that the frequencies match better with a specially devised just intonation scale, than with the equal tempered alternative. The measured music intervals still deviated, and we discuss some practical and stylistic reasons for this. We do make the reservation, that our specific conclusions are constrained only the the Javanese Gamelan ensemble at Arizona State University, but using other literature on Gamelan tuning, we entertain possibilities for all tuning systems in Gamelan music culture.


I received my Bachelor of Science in Economics from the WP Carey school of business at Arizona State University. During my time at ASU I took Dr Ted Solis’ Gamelan Ensemble class twice, the first time for a necessary humanities credit and the second time for my own pleasure. I am currently not a student at ASU, but Dr Solis has been generous enough to let me participate in his fall 2015 Gamelan Ensemble class.

I was not a student of music, but I am an everyday musician and I have self studied various areas of music. I would estimate that I have read about 1,500 pages of academic music material. For this paper, Harry Partch’s ‘Genesis of a Music’ has been most insightful, providing me with a good understanding of the history, mechanics, and mathematics of tuning systems from around the world.

Brief Overview of Gamelan music

Gamelan is a traditional style of music from Indonesia. The word ‘Gamelan’ translated into english roughly means ‘Orchestra’, but within this paper ‘Gamelan’ will refer to the music culture itself, rather than the collection of instruments. To refer to the collection of instruments I will use ‘Gamelan orchestra’. Gamelan orchestras are percussive, and largely contain gongs and metallophones1.

Gamelan orchestras, quite unlike the ensembles in other music cultures, are each uniquely tuned. There is no Gamelan-wide tuning standard, only orchestra specific tunings. This means that one could not use a Gamelan instrument from one orchestra in a another orchestra, for the instruments would not be in tune with each other. This is in contrast with European music culture, where every instrument, regardless as to what ensemble it plays in, is tuned the same. One could say, European tuning is a culture wide standard, and Gamelan tuning is an ensemble wide standard.

In addition to the great variation of tunings between Gamelan orchestras, the tuning is exclusively done by a religious class of people in Indonesia who keep essential aspects of Gamelan orchestra production a trade secret. There is no body of work from the instrument makers explaining the theory behind Gamelan tuning.

While the tuning of Gamelan orchestras are various and mysterious, there are norms and consistencies that span Gamelan music. For example, all Gamelan instruments are are in one of two tuning systems, called Slendro and Pelog. Slendro and Pelog are distinct and separate collections of tones, unlike European scales, which are subsets of a larger collection of tones (C major being an 8 tone subset of the greater 12 tones).

  1. Metallophones being instruments with metal bars, and Gongs being instruments with metal disks.