Rock music is a genre of popular music that originated as "rock and roll" in the United States in the 1950s, and developed into a range of different styles in the 1960s and later, particularly in the United Kingdom and the United States.〔W. E. Studwell and D. F. Lonergan, ''The Classic Rock and Roll Reader: Rock Music from its Beginnings to the mid-1970s'' (Abingdon: Routledge, 1999), ISBN 0-7890-0151-9〕 It has its roots in 1940s' and 1950s' rock and roll, itself heavily influenced by blues, rhythm and blues and country music. Rock music also drew strongly on a number of other genres such as electric blues and folk, and incorporated influences from jazz, classical and other musical sources.
Musically, rock has centered on the electric guitar, usually as part of a rock group with electric bass guitar and drums. Typically, rock is song-based music usually with a 4/4 time signature using a verse-chorus form, but the genre has become extremely diverse. Like pop music, lyrics often stress romantic love but also address a wide variety of other themes that are frequently social or political in emphasis. The dominance of rock by white, male musicians has been seen as one of the key factors shaping the themes explored in rock music. Rock places a higher degree of emphasis on musicianship, live performance, and an ideology of authenticity than pop music.
By the late 1960s, referred to as the "golden age"〔Turner, Luke. (How "The Baby Boomers Stole Music With Myths Of A Golden Age" ). ''The Quietus.com''. October 3rd, 2013. Retrieved 21-1-14〕 or "classic rock"〔 period, a number of distinct rock music subgenres had emerged, including hybrids like blues rock, folk rock, country rock, raga rock, and jazz-rock fusion, many of which contributed to the development of psychedelic rock, which was influenced by the countercultural psychedelic scene. New genres that emerged from this scene included progressive rock, which extended the artistic elements; glam rock, which highlighted showmanship and visual style; and the diverse and enduring subgenre of heavy metal, which emphasized volume, power, and speed. In the second half of the 1970s, punk rock reacted against the perceived overblown, inauthentic and overly mainstream aspects of these genres to produce a stripped-down, energetic form of music valuing raw expression and often lyrically characterised by social and political critiques. Punk was an influence into the 1980s on the subsequent development of other subgenres, including new wave, post-punk and eventually the alternative rock movement. From the 1990s alternative rock began to dominate rock music and break through into the mainstream in the form of grunge, Britpop, and indie rock. Further fusion subgenres have since emerged, including pop punk, rap rock, and rap metal, as well as conscious attempts to revisit rock's history, including the garage rock/post-punk and synthpop revivals at the beginning of the new millennium.
Rock music has also embodied and served as the vehicle for cultural and social movements, leading to major sub-cultures including mods and rockers in the UK and the hippie counterculture that spread out from San Francisco in the US in the 1960s. Similarly, 1970s punk culture spawned the visually distinctive goth and emo subcultures. Inheriting the folk tradition of the protest song, rock music has been associated with political activism as well as changes in social attitudes to race, sex and drug use, and is often seen as an expression of youth revolt against adult consumerism and conformity.
== Characteristics ==
The sound of rock is traditionally centered on the electric guitar, which emerged in its modern form in the 1950s with the popularization of rock and roll,〔J. M. Curtis, ''Rock Eras: Interpretations of Music and Society, 1954–1984'' (Madison, WI: Popular Press, 1987), ISBN 0-87972-369-6, pp. 68–73.〕 and was influenced by the sounds of electric blues guitarists.〔Michael Campbell & James Brody, (Rock and Roll: An Introduction ), pages 80-81〕 The sound of an electric guitar in rock music is typically supported by an electric bass guitar pioneered in jazz music in the same era, and percussion produced from a drum kit that combines drums and cymbals. This trio of instruments has often been complemented by the inclusion of others, particularly keyboards such as the piano, Hammond organ and synthesizers.〔P. Théberge, ''Any Sound you can Imagine: Making Music/Consuming Technology'' (Middletown, CT, Wesleyan University Press, 1997), ISBN 0-8195-6309-9, pp. 69–70.〕 The basic rock instrumentation was adapted from the basic blues band instrumentation (prominent lead guitar, second chord instrument, bass, and drums).〔 A group of musicians performing rock music is termed a rock band or rock group and typically consists of between two and five members. Classically, a rock band takes the form of a quartet whose members cover one or more roles, including vocalist, lead guitarist, rhythm guitarist, bass guitarist, drummer and often that of keyboard player or other instrumentalist.
Rock music is traditionally built on a foundation of simple unsyncopated rhythms in a 4/4 meter, with a repetitive snare drum back beat on beats two and four.〔C. Ammer, ''The Facts on File Dictionary of Music'' (New York, NY: Infobase, 4th edn., 2004), ISBN 0-8160-5266-2, pp. 251–2.〕 Melodies are often derived from older musical modes, including the Dorian and Mixolydian, as well as major and minor modes. Harmonies range from the common triad to parallel fourths and fifths and dissonant harmonic progressions.〔 Rock songs, since the late 1950s〔Michael Campbell & James Brody (2007), ''Rock and Roll: An Introduction'', (page 117 )〕 and particularly from the mid-1960s onwards, often used the verse-chorus structure derived from blues and folk music, but there has been considerable variation from this model.〔J. Covach, "From craft to art: formal structure in the music of the Beatles", in K. Womack and Todd F. Davis, eds, ''Reading the Beatles: Cultural Studies, Literary Criticism, and the Fab Four'' (New York, NY: SUNY Press, 2006), ISBN 0-7914-6715-5, p. 40.〕 Critics have stressed the eclecticism and stylistic diversity of rock.〔T. Gracyk, ''Rhythm and Noise: an Aesthetics of Rock'', (London: I. B. Tauris, 1996), ISBN 1-86064-090-7, p. xi.〕 Because of its complex history and tendency to borrow from other musical and cultural forms, it has been argued that "it is impossible to bind rock music to a rigidly delineated musical definition."〔P. Wicke, ''Rock Music: Culture, Aesthetics and Sociology'' (Cambridge: Cambridge University Press, 1990), ISBN 0-521-39914-9, p. x.〕
Unlike many earlier styles of popular music, rock lyrics have dealt with a wide range of themes in addition to romantic love: including sex, rebellion against "The Establishment", social concerns and life styles.〔 These themes were inherited from a variety of sources, including the Tin Pan Alley pop tradition, folk music and rhythm and blues.〔B. A. Farber, ''Rock 'n' roll Wisdom: What Psychologically Astute Lyrics Teach About Life and Love'' (Westport, CT: Greenwood, 2007), ISBN 0-275-99164-4, pp. xxvi-xxviii.〕 Music journalist Robert Christgau characterizes rock lyrics as a "cool medium" with simple diction and repeated refrains, and asserts that rock's primary "function" "pertains to music, or, more generally, noise." The predominance of white, male and often middle class musicians in rock music has often been noted〔C. McDonald, ''Rush, Rock Music and the Middle Class: Dreaming in Middletown'' (Bloomington, IN: Indiana University Press, 2009), ISBN 0-253-35408-0, pp. 108–9.〕 and rock has been seen as an appropriation of black musical forms for a young, white and largely male audience.〔S. Waksman, ''Instruments of Desire: the Electric Guitar and the Shaping of Musical Experience'' (Cambridge, MA: Harvard University Press, 2001), ISBN 0-674-00547-3, p. 176.〕 As a result, it has been seen as articulating the concerns of this group in both style and lyrics.〔S. Frith, ''Taking Popular Music Seriously: Selected Essays'' (Aldershot: Ashgate, 2007), ISBN 0-7546-2679-2, pp. 43–4.〕
Since the term rock began to be used in preference to rock and roll from the late-1960s, it has often been contrasted with pop music, with which it has shared many characteristics, but from which it is often distanced by an emphasis on musicianship, live performance and a focus on serious and progressive themes as part of an ideology of authenticity that is frequently combined with an awareness of the genre's history and development.〔T. Warner, ''Pop Music: Technology and Creativity: Trevor Horn and the Digital Revolution'' (Aldershot: Ashgate, 2003), ISBN 0-7546-3132-X, pp. 3–4.〕 According to Simon Frith "rock was something more than pop, something more than rock and roll. Rock musicians combined an emphasis on skill and technique with the romantic concept of art as artistic expression, original and sincere".〔 In the new millennium the term ''rock'' has sometimes been used as a blanket term including forms such as pop music, reggae music, soul music, and even hip hop, with which it has been influenced but often contrasted through much of its history.〔R. Beebe, D. Fulbrook and B. Saunders, "Introduction" in R. Beebe, D. Fulbrook, B. Saunders, eds, ''Rock Over the Edge: Transformations in Popular Music Culture'' (Durham, NC: Duke University Press, 2002), ISBN 0-8223-2900-X, p. 7.〕
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