In Indonesia, gamelan usually accompanies dance, wayang puppet performances, or rituals or ceremonies. Typically players in the gamelan will be familiar with dance moves and poetry, while dancers are able to play in the ensemble. In wayang, the dalang (puppeteer) must have a thorough knowledge of gamelan, as he gives the cues for the music. Gamelan can be performed by itself - in "klenengan" style, or for radio broadcasts - but concerts in the Western style are not traditional.
Gamelan's role in rituals is so important that there is a Javanese saying that "It's not official until the gong is hung." Some performances are associated with royalty, such as visits by the sultan of Yogyakarta. Certain gamelans are associated with specific rituals, such as the Gamelan Sekaten, which is used in celebration of Mawlid an-Nabi (Muhammad's birthday). In Bali, almost all religious rituals include gamelan performance. Gamelan is also used in the ceremonies of the Catholic church in Indonesia. Certain pieces are designated for starting and ending performances or ceremonies. When a "leaving" piece (such as "Udan Mas") is begun, the audience will know that the event is nearly finished and will begin to leave. Certain pieces are also believed to possess magic powers, and can be used to ward off evil spirits.
Gamelan is frequently played on the radio. For example, the Pura Pakualaman gamelan performs live on the radio every Minggu Pon (a day in the 35-day cycle of the Javanese calendar). In major towns, the Radio Republik Indonesia employs professional musicians and actors, and broadcast programs of a wide variety of gamelan music and drama.
In the court tradition of central Java, gamelan is often played in the pendopo, an open pavilion with a cavernous, double-pitched roof, no side walls, and a hard marble or tile floor. The instruments are placed on a platform to one side, which allows the sound to reverberate in the roof space and enhances the acoustics.
In Bali, the Gamelan instruments are all kept together in the balai banjar, a community meeting hall which has a large open space with a roof over top of it with several open sides. The instruments are all kept here together because they believe that all of the instruments belong to the community as a whole and no one person has ownership over an instrument. Not only is this where the instruments are stored, but this is also the practice space for the sekaha (Gamelan orchestra). The open walls allow for the music to flow out into the community where the rest of the people can enjoy it.
The sekaha is led by a single instructor whose job it is in the community to lead this group and to come up with new songs. When they are working on a new song, the instructor will lead the group in practice and help the group form the new piece of music as they are practicing. When the instructor creates a new song, he leaves enough open for interpretation that the group can improvise and as a group they will be writing the music as they are practicing it.
The Balinese Gamelan groups are constantly changing their music by taking older pieces they know and mixing them together as well as trying new variations on their music. Their music is always constantly changing because they believe that music should grow and change; the only exception to this is with their most sacred songs which they will not change. A single new piece of music can take several months before it is completed.
Men and women usually perform in separate groups, with the exception of the pesindhen, the female singer who performs with male groups.
In the West, gamelan is often performed in a concert context, but may also incorporate dance or wayang.