Acid rock in the context of "Distortion (music)"

Heavy metal (or simply metal) is a genre of rock music that developed in the late 1960s and early 1970s, largely in the United Kingdom and United States. With roots in blues rock, psychedelic rock and acid rock, heavy metal bands developed a thick, monumental sound characterized by distorted guitars, extended guitar solos, emphatic beats and loudness.

In 1968, three of the genre's most famous pioneers – British bands Led Zeppelin, Black Sabbath and Deep Purple – were founded. Though they came to attract wide audiences, they were often derided by critics. Several American bands modified heavy metal into more accessible forms during the 1970s: the raw, sleazy sound and shock rock of Alice Cooper and Kiss; the blues-rooted rock of Aerosmith; and the flashy guitar leads and party rock of Van Halen. During the mid-1970s, Judas Priest helped spur the genre's evolution by discarding much of its blues influence, while Motörhead introduced a punk rock sensibility and an increasing emphasis on speed. Beginning in the late 1970s, bands in the new wave of British heavy metal such as Iron Maiden and Saxon followed in a similar vein. By the end of the decade, heavy metal fans became known as "metalheads" or "headbangers". The lyrics of some metal genres became associated with aggression and machismo, an issue that has at times led to accusations of misogyny.

Psychedelic music (sometimes called psychedelia) is a wide range of popular music styles and genres influenced by 1960s psychedelia, a subculture of people who used psychedelic drugs such as DMT, LSD, mescaline, and psilocybin mushrooms, to experience synesthesia and altered states of consciousness. Psychedelic music may also aim to enhance the experience of using these drugs and has been found to have a significant influence on psychedelic therapy.

Psychedelia embraces visual art, movies, and literature, as well as music. Psychedelic music emerged during the 1960s among folk and rock bands in the United States and the United Kingdom, creating the subgenres of psychedelic folk, psychedelic rock, acid rock, and psychedelic pop before declining in the early 1970s. Numerous spiritual successors followed in the ensuing decades, including progressive rock, krautrock, and heavy metal. Since the 1970s, revivals have included psychedelic funk, neo-psychedelia, and stoner rock as well as psychedelic electronic music genres such as acid house, trance music, and new rave.

Psychedelic rock is a subgenre of rock music that originally emerged during the mid-1960s, inspired by psychedelic culture and primarily centered around the influence of psychoactive and hallucinogenic drugs. The music incorporated new electronic sound effects and recording techniques, extended instrumental solos, and improvisation. Many psychedelic groups differ in style with the label often applied spuriously.

Originating in the mid-1960s among British and American musicians, the sound of psychedelic rock invokes three core effects of LSD: depersonalization, dechronicization (the bending of time), and dynamization (when fixed, ordinary objects dissolve into moving, dancing structures), all of which detach the user from everyday reality. Musically, the effects may be represented via novelty studio tricks, electronic or non-Western instrumentation, disjunctive song structures, and extended instrumental segments. Some of the earlier 1960s psychedelic rock musicians were based in folk, jazz, and the blues, while others showcased an explicit Indian classical influence called "raga rock". In the 1960s, there existed two main variants of the genre: the more whimsical, surrealist British psychedelia and the harder American West Coast "acid rock". While "acid rock" is sometimes deployed interchangeably with the term "psychedelic rock", it also refers more specifically to the heavier, harder, and more extreme ends of the genre.