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. 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 and rock has been seen as an appropriation of black musical forms for a young, white and largely male audience. As a result, it has been seen as articulating the concerns of this group in both style and lyrics. Musically, rock has centered on the electric guitar, usually as part of a rock group with electric bass guitar and drums. 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 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. in the early 1960s [the term] 'pop music' competed terminologically with Beat music [in England], while in the USA its coverage overlapped (as it still does) with that of 'rock and roll'".
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. Similarly, 1970s punk culture spawned the visually distinctive goth and emo subcultures. As a genre, pop music is extremely eclectic, often borrowing elements from other styles including urban, dance, rock, Latin and country; nonetheless, there are core elements which define pop.
In the 1940s improved microphone design allowed a more intimate singing style and ten or twenty years later inexpensive and more durable 45 r.p.m. Such elements include generally short to medium-length songs, written in a basic format (often the verse-chorus structure), as well as the common employment of repeated choruses, melodic tunes, and hooks. 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. 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. Pop music (a term that originally derives from an abbreviation of "popular") is a genre of popular music, which originated in its modern form in the Western world during the 1950s and 1960s, deriving from rock and roll. The dominance of rock by white, male musicians has been seen as one of the key factors shaping the themes explored in rock music. From about 1967 the term was increasingly used in opposition to the term rock music, a division that gave generic significance to both terms. Whereas rock aspired to authenticity and an expansion of the possibilities of popular music, pop was more commercial, ephemeral and accessible. According to Simon Frith pop music is produced "as a matter of enterprise not art", is "designed to appeal to everyone" and "doesn't come from any particular place or mark off any particular taste". 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. According to Simon Frith "rock was something more than pop, something more than rock and roll. The dominance of rock by white, male musicians has been seen as one of the key factors shaping the themes explored in rock music.