System of a Down is an Armenian-American heavy metal band formed in Glendale, California, in 1994. Since 1997, the lineup has consisted of Serj Tankian (lead vocals, keyboards), Daron Malakian (guitar, vocals), Shavo Odadjian (bass), and John Dolmayan (drums), who replaced original drummer Andy Khachaturian. The band achieved commercial success with the release of five studio albums, three of which debuted at number one on the US Billboard 200 chart.