The Angklung is a musical instrument made of two bamboo tubes attached to a bamboo frame. The tubes are carved to have a resonant pitch when struck and are tuned to octaves. The base of the frame is held in one hand, whilst the other hand shakes the instrument rapidly. This causes a repeating note to sound. Each of three or more performers in an angkalung ensemble play just one note or more, but altogether complete melodies are produced. The Angklung is popular throughout Southeast Asia, but it originated in today's Indonesia and has been played by the Sundanese for many centuries.
In Bali, an ensemble of angklung is called gamelan angklung (anklung). While the ensemble gets its name from the bamboo shakers, these days most compositions for Gamelan Angklung do not use them. An ensemble of mostly bronze metallophones is used instead, generally with about 20 musicians.
While the instrumentation of gamelan angklung is similar to gamelan gong kebyar, it has several critical differences. First, the instruments are tuned to a 5-tone slendro scale, though actually most ensembles use a four-tone mode of the five-tone scale played on instruments with four keys. An exception is the five-tone angklung from the north of Bali. But even in four-tone angklung groups, the flute players will occasionally touch on the fifth implied tone. Secondly, whereas many of the instruments in gong kebyar span multiple octaves of its pentatonic scale, mosts gamelan angklung instruments only contain one octave, although some five-tone ensembles have roughly an octave and a half. The instruments are considerably smaller than those of the gong kebyar.
Gamelan angklung is often heard in Balinese temples, where it supplies musical accompaniment to temple anniversaries (odalan). It is also characteristic of rituals related to death, and therefore connected in Balinese culture to the invisible spiritual realm and transitions from life to death and beyond. Because of its portability, gamelan angklung may be carried in processions while a funeral bier is carried from temporary burial in a cemetery to the cremation site. The musicians also often play music to accompany the cremation ceremony. Thus many Balinese listeners associate angklung music with strong emotions evoking a combination of sacred sweetness and sadness.
The structure of the music is similar to gong kebyar, although employing a four tone scale. Jublag and jegog carry the basic melody, which is elaborated by gangsa, reyong, ceng-ceng, drum, and flute. A medium sized gong, called kempur, is generally used to punctuate a piece's major sections.
Most older compositions do not employ gong kebyar's more ostentatious virtuosity and showmanship. Recently many Balinese composers have created kebyar-style works for gamelan angklung or have rearranged kebyar melodies to fit the angklung's more restricted four tone scale. These new pieces often feature dance, so the gamelan angklung is augmented with more gongs and heavier gongs. Additionally, some modern composers have created experimental instrumental pieces for the gamelan angklung.