Sunn O))) is named after the Sunn amplifier brand, whose logo includes a circle next to the “SUNN” banner with waves heading off to the right. In interviews, Stephen O’Malley stated that the band’s moniker was also chosen as a play on the name Earth, a band widely regarded as pioneers of drone music throughout the 1990s. Before the band members moved to Los Angeles, it briefly used the moniker Mars.
The band’s style is characterized by extremely slow tempos, heavily distorted guitars, avoidance of rhythm and melody, and alternate tunings. The guitars are notable for their incredibly low register, frequently utilising tunings as low as drop A. Additionally, the band is known for using resonant feedback to create monolithic soundscapes and eerie atmospheres. Percussion is almost never incorporated, with a lack of any discernible beat. When performing live, the band wears robes, fills the air with fog, and plays at an extremely high volume.