Inspired by the darker sonic explorations of the Grateful Dead and Pink Floyd, this strain of psychedelia focused on the mind-altering effects of L.S.D. and the loud volume of Black Sabbath. In the '60s and early '70s, plenty of bands were experimenting with chemicals, but only a few were trying to musically re-create the sensory distortions of an acid trip. They usually relied on heavily distorted guitars, electronic and tape-phase effects, and a certain apocalyptic mindset. Jimi Hendrix used backwards-masked tape-splicing and multilayered guitars, while Steppenwolf created the definitive acid rock anthem “Born to Be Wild” with a driving beat, distorted guitars, and anti-authoritarian lyrics. Many others followed, from the proto-sludge rock of Blue Cheer to the droning space meditations of Hawkwind. Acid rock went into remission when the mindset of the American counterculture turned darker in the early '70s, though its spirit can now be heard reflected in the new school of stoner rock bands like Monster Magnet, Comets on Fire, and Queens of the Stone Age.

Notable Artists: Iron Butterfly, the Electric Prunes, Blue Cheer