Two parallel revolutions happened in the 1970s-90s: hip-hop built a new culture from turntables and samplers in the Bronx; electronic music built new sounds from synthesizers in Europe. Both dominate the 21st century.
The period from 1970 to 2000 saw technology fundamentally and repeatedly reshape the conditions under which music was made, distributed, experienced, and economically organized. Each decade brought a new technological disruption that altered the creative landscape: the 1970s saw the democratization of multitrack recording and the emergence of synthesizers as primary compositional tools; the 1980s saw the digital revolution arrive in studios, homes, and dance clubs simultaneously; the 1990s saw the internet begin to dissolve the physical distribution infrastructure on which the music industry had depended for a century. The period's most consequential musical development was, however, not technological but cultural: the emergence of hip-hop from the Black and Latino communities of the South Bronx in New York City in the early 1970s, and its development into the dominant popular music of the late twentieth century.
Hip-hop's foundational moment is typically located at a back-to-school party organized by DJ Kool Herc (Clive Campbell) at 1520 Sedgwick Avenue in the South Bronx on August 11, 1973. Herc, a Jamaican immigrant who had brought the Jamaican sound system tradition to New York, discovered that the dancers at his parties were most animated during the percussion-heavy instrumental breaks that occurred in funk and soul records. He began extending these breaks by playing two copies of the same record simultaneously on two turntables, alternating between them when each break ended to create a continuous loop — the 'Merry-Go-Round' technique. This innovation created a new musical form: not a recording of a performance but a live reconstruction and extension of recorded material, using the turntable as a compositional instrument. Grandmaster Flash developed the technique further with precision cueing and scratching; Afrika Bambaataa added electronic elements from German electronic music, particularly Kraftwerk, whose Trans-Europe Express (1977) and The Man-Machine (1978) provided drum machine patterns and synthesizer textures that would directly inspire both hip-hop production and the Chicago house and Detroit techno that emerged in the following decade. The lyrical dimension of hip-hop — the MC's verbal performance over the DJ's musical backdrop — developed through competitive verbal improvisation at block parties into a poetic tradition with its own aesthetic standards of wordplay, rhythmic complexity, and cultural specificity.
Chicago house music grew in the early-to-mid 1980s out of the Warehouse nightclub and its DJ Frankie Knuckles, creating a new form of electronic dance music by combining drum machines (primarily the Roland TR-808 and TR-909), synthesizer bass lines, and the gospel-inflected soulful vocals of Black Chicago house music culture. Detroit techno, developed slightly later by Juan Atkins, Derrick May, Kevin Saunderson, and a circle of musically educated Black Detroiters who had grown up in the shadow of the city's automotive collapse, took Kraftwerk's futurism and applied it to the social reality of deindustrialized America, creating music that was harder, more abstract, and more explicitly technological than Chicago house. Both scenes were predominantly Black and working-class, and Chicago house grew out of a largely gay club culture — facts that were systematically elided as house and techno were adopted by predominantly white European audiences and became the foundation of rave culture, electronic dance music, and eventually the global club industry. Affordable samplers — the E-mu SP-1200 and Akai S900, and from 1988 Akai's MPC60 — gave hip-hop producers hardware for precisely programming and manipulating samples from existing recordings; combined with the increasingly liberal use of samples from James Brown, Parliament-Funkadelic, and dozens of other sources, they made possible the dense, layered, allusive production of Public Enemy's It Takes a Nation of Millions to Hold Us Back (1988) and the foundational albums of the golden age of hip-hop. The compact disc, introduced commercially in 1982, replaced vinyl as the dominant physical medium by the early 1990s; the MP3 compression format, developed by the Fraunhofer Institute and standardized in 1993, made digital audio files small enough to transfer over the internet; and Napster's peer-to-peer file-sharing service, launched in 1999, made the illegal copying and distribution of music trivially easy for anyone with a computer. By 2000, the digital disruption of the music industry's physical distribution model was underway and unstoppable. The period from 1970 to 2000 also saw the full development of album-era rock into its most elaborate forms: the concept album, which reached its commercial and artistic peak with Pink Floyd's The Dark Side of the Moon (1973, which remained on the Billboard album chart for a total of 741 weeks between 1973 and 1988) and The Wall (1979); the stadium rock phenomenon, which transformed performance from an intimate experience into a mass spectacle; and eventually the alternative rock underground that developed in the 1980s through independent labels like SST Records, Twin/Tone and Homestead, nurturing artists like Black Flag, Hüsker Dü, the Replacements, and Sonic Youth whose commercial influence was minimal but whose aesthetic influence on 1990s rock was enormous. The 1980s also saw Michael Jackson's Thriller establish new commercial ceilings for popular music and MTV establish the music video as a primary medium for musical promotion, fundamentally shifting the relative importance of visual presentation in an artist's commercial strategy. The convergence of these currents — hip-hop, electronic dance music, alternative rock, global pop — created the complex, genre-fluid landscape of popular music that the digital revolution of the 2000s would both accelerate and fragment further. The 1990s also saw hip-hop's commercial and cultural apotheosis: the East Coast-West Coast rivalry between Bad Boy Records (Notorious B.I.G., Puff Daddy) and Death Row Records (Tupac Shakur, Dr. Dre, Snoop Dogg) generated some of the decade's most commercially successful and culturally significant recordings while ending in the deaths of both its central figures. Dr. Dre's production innovations on albums like The Chronic (1992) and 2001 (1999) established West Coast g-funk as a dominant aesthetic in hip-hop production and demonstrated that hip-hop could match mainstream rock and pop in production sophistication. Simultaneously, the alternative rock underground broke through commercially with Nirvana's Nevermind (1991), followed by Pearl Jam, Soundgarden, and dozens of other Pacific Northwest and independent-label bands whose success briefly made guitar-driven rock the dominant commercial format before the mid-decade rise of pop-oriented formats reasserted mainstream pop's dominance. The period ended with the music industry's revenue model intact but its technological foundations already collapsing beneath it.