American alternative metal band formed in Sacramento, California in 1988. They were formed by Chino Moreno, Stephen Carpenter, Abe Cunningham, and Dominic Garcia. During their first five years, the band's lineup changed several times, but stabilized in 1993 when Cunningham rejoined after his departure in 1990; by this time, Chi Cheng was bassist. The lineup remained stable for fifteen years, with the exception of keyboardist and turntablist Frank Delgado being added in 1999. The band's experimental nature has led some critics to describe them as "the Radiohead of metal".