A gamelan is the name given to the set of instruments used to perform traditional music played in Java, Indonesia and Bali. The music is important part of traditional life and is heard at celebrations and performances. The music is an oral tradition. A gamelan consists mainly of gongs, metallophones (instruments with rows of tuned metal bars that are struck with mallets) and drums. Some gamelans include bamboo flutes (suling), bowed strings (rebab) and vocalists. Each gamelan is tuned slightly differently, which gives them all their own unique sound. Two different tuning systems are used; a 5-note scale (slendro) and a 7-note scale (pelog). A hand drum, called a kendhang, is important for controlling tempo and rhythm.