|Stylistic Origins:||Psychedelic rock, garage rock, blues-rock, jazz fusion, rāga|
|Cultural Origins:||Late 1960s United States|
|Instruments:||Electric guitar (usually with guitar effects - distortion, fuzzbox, phaser, etc.) - bass guitar - drums|
|Popularity:||Peaked in the late 1960s and early 1970s|
|Derivatives:||Heavy metal, space rock|
|Regional Scenes:||San Francisco, California|
Acid rock is a form of psychedelic rock, which is characterized with long instrumental solos, few (if any) lyrics and musical improvisation . Tom Wolfe describes the LSD-influenced music of The Jimi Hendrix Experience, The Doors, Cream, Jefferson Airplane, New Riders of the Purple Sage and the Grateful Dead as "acid rock" in his book about Ken Kesey and the Acid Tests, The Electric Kool-Aid Acid Test.
"Acid rock" also refers to the subset of psychedelic rock bands that were part of, or were influenced by, the San Francisco Sound, and which played loud, "heavy" music featuring long improvised solos.
Acid rock got its name ("acid" being a slang term for LSD) because it served as "background" music for acid trips in underground parties in the 1960s (e.g. the Merry Pranksters' "Acid Tests"). In an interview with Rolling Stone Jerry Garcia quoted band member Phil Lesh stating, "acid rock is what you listen to when you are high on acid." Garcia further stated there is no real psychedelic rock and that it is Indian classical music and some Tibetan music that are examples of music "designed to expand consciousness." The term "acid rock" is generally equivalent to psychedelic rock. Rolling Stone magazine includes early Pink Floyd as "acid-rock". In 1968 Life magazine referred to The Doors as the "Kings of Acid Rock".
The term was much used in its heyday of the late 1960s and early 1970s, but has fallen into disuse; it is now only used as a means of putting this music into historical perspective.
When hard rock and heavy metal became prominent in the early and mid 1970s, the phrase "acid rock" was sometimes generically and erroneously applied to these genres. Over time, the common use of the term "heavy metal" replaced "acid rock" for these styles of music. Examples of hard rock bands once commonly called "acid rock" are Led Zeppelin , Alice Cooper and Deep Purple.
Historically and more accurately, the term refers to the relationship between music and LSD, commonly called "acid". "Acid rock" can connote music recorded under the influence of LSD, or intended to be experienced in conjunction with LSD. These associations can be a matter of the musician's intention, the listener's intention, or even just a general perception on the part of the person using the term. Often the lyrics deal with drug-induced psychological themes as well as references to mind-altering techniques.
Characterized by an off-beat style, vivid imagery, and sometimes strange sound/musical effects (e.g. backward recorded music) , acid rock often settles into a hypnotic groove wherein a listener (and possibly even the band) can "get lost" within a song.