As Eastern instrumentation goes, the gamelan is an odd duck. Most people with some minimal exposure to world music will recognize the gamelan by name, but will be hard pressed to describe its appearance or sound.

That’s partly because the gamelan is a musical chameleon. As Between Heaven & Earth‘s liner notes put it, a gamelan is “a set of tuned percussion instruments, usually comprising gongs, metallophones and gong-chimes, generally made of bronze, but occasionally iron or even bamboo.” Most gamelan instruments are arranged in pairs with very slightly different tunings; when struck or keyed, they create the gamelan’s characteristic undulating melody, which can sound quite creepy in the bass range.

While there are many gamelan styles, gamelan music consists of fairly standardized elements. There’s a low-end “anchor” melody provided by bass-tuned keyed instruments, which is embellished by higher-tuned instruments and punctuated by gongs. Drums or other gongs are used to maintain a consistent rhythm.

The six pieces on Between Heaven and Earth highlight three gamelans. Gender wayang, a quartet of ten-keyed metallophones playing music in a complex 5-note scale, is the most striking, hinting at a musical history entwined with that of India. Balinese religion is a localized variation upon Hinduism, and during Balinese religious festivals gender wayang provides accompaniment to stories drawn from the Mahabharata.

Gamelan Semar Pegulingan, which uses a seven-note scale, was a court gamelan during the days of Bali’s royalty. It used to play outside the king’s bedchamber, which perhaps accounts for the vigorous pace of the piece included here.

Gamelan Jegog is the closest thing to “pop” gamelan—a modern gamelan variant partial to xylophone-type keyed instruments made of bamboo, some of which are quite massive. The Jegog style began in west Bali, where bamboo is plentiful, making the bamboo gamelan the Balinese equivalent of a harmonica or comb-and-tissue-paper. The tones obtained from these instruments aren’t as clear and ringing as you’d get from metallophones, but they’re very distinctive. They seem to embody weather-related concepts particularly well, especially in the bass register—the up-down-up-down rhythm is as visceral as the air before a thunderstorm.

Offering only six tracks (which vary in length from under 3 to over 25 minutes), Between Heaven and Earth doesn’t seem to offer the best introduction to gamelan, particularly with about 75% of its length devoted to three lengthy gamelan Jegog pieces. A more equitable division of styles might help. The album’s liner notes, however, provide a concise and data-intensive introduction to gamelan; read carefully, it should leave you sufficiently conversant in gamelan styles to chart the course of your own explorations beyond Between Heaven and Earth.