Gamelan music belongs at once to the royal courts and to the villages. It defies classification according to the European categories of "classical" and "folk" music, since it has elements of both: musicians may be highly trained—or not; notation may be a means of transmission—or not; composers of pieces are often known, but not usually named; some performance styles have a wide distribution, but others are highly localized; the music may stand on its own as concert music, or may accompany other activities; and audiences may be drawn from urban or rural areas, from high or low social classes. Like all of the world's musical traditions, gamelan music has been adjusted to fit changing conditions. While it is considered Java's traditional music par excellence, it continues to evolve in unpredictable ways, and has been overtaken in popularity by genres that use Western-tuned guitars or electronic keyboards.
The gamelan is not an instrument, but a whole set of instruments that are tuned to each other and played together by a group of musicians. It is indigenous to Java and Bali, but is now to be found in many parts of the world, even in places where there are few Indonesians: in the U.S. alone there are around 200 gamelans of various types. The gamelan can accommodate a wide range of musical skill, which is one of the reasons for its global popularity as an amateur ensemble. The ensemble is made up primarily of tuned, bronze percussion, but includes other instruments—and voices—as well. A standard modern ensemble is actually a double set, each set tuned to a different string of intervals, none of which correspond to the basic building blocks of Western music (there are no minor or major seconds, no minor or major thirds). The two tunings are called pélog and sléndro, and within each tuning there are three melodic modes.
The many simultaneous melodies played on the gamelan do not form chords. In fact, except for rare exceptions, the music is not based on any harmonic system at all. Rather, everyone follows the same basic reference melody (called the balungan), which is the tune that is written down if notation is used. By referring to this melody, experienced musicians can derive their respective parts according to the distinctive language of each instrument. The reverse is also true—one can derive the reference melody from many of the other parts—which is why collective memory is stronger than individual memory. The result of this layering of multiple interpretations of the same melody is highly structured, albeit with a strong element of serendipity, since there is leeway on some of the parts, and, with good musicians, one never knows in advance what the overall combination will yield.
This is music that says “all is well in the world”—it is a comforting sound, one that may be said to reflect ideal forms of human interaction. There are leaders, both rhythmic and melodic, but, true to the traditional Javanese ideal of leadership, they lead by suggestion, not by coercion, and all parts are ultimately considered to be equally important—and this applies, as well, to the singers, although in current practice the female soloist is miked.