Slendro

Slendro (called salendro by the Sundanese) is a pentatonic scale,  Play  the older of the two most common scales (laras) used in Indonesian gamelan music, the other being pélog. In Javanese the term is said to derive either from "Sailendra", the name of the ruling family in the eighth and ninth centuries when Borobudur was built, or from its earlier being given by the god Sang Hyang Hendra.

From one region of Indonesia to another the slendro scale often varies widely. The amount of variation also varies from region to region. For example, slendro in Central Java varies much less from gamelan to gamelan than it does in Bali, where ensembles from the same village may be tuned very differently. The five pitches of the Javanese version are roughly equally spaced within the octave.

As in pelog, although the intervals vary from one gamelan to the next, the intervals between notes in a scale are very close to identical for different instruments within the same gamelan. It is common in Balinese gamelan that instruments are played in pairs which are tuned slightly apart so as to produce interference beating which are ideally at a consistent speed for all pairs of notes in all registers. It is thought that this contributes to the very "busy" and "shimmering" sound of gamelan ensembles. In the religious ceremonies that contain gamelan, these interference beats are meant to give the listener a feeling of a god's presence or a stepping stone to a meditative state.

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Wikipedia