Minimalism was both a compromise and a rejection of serialism and indeterminacy. It had no narrative/emotional development, but it was mostly tonal. It managed this feat by using repetition of minimal tonal units. It overcame the inherent limitation of those simple units by letting gradual variations alter the composition slowly over time. By their nature, minimalist compositions emphasized trance instead of reasoning. They emanated spirituality instead of irreverence. La Monte Young (USA, 1935), a pupil of John Cage, composed his first music for sustained tones in 1957. Two years later he would found the "Fluxus" movement of musicians and artists. The term "minimalism" originally referred to his "dream house", a New York loft in which Young and his Theater Of Eternal Music (comprising violinist Tony Conrad, viola player John Cale, trumpet player Jon Hassell, keyboardist Terry Riley and others) developed a music made of semi-stationary waves, of slowly evolving amorphous sound. Music became a living organism. Colossal pieces such as The Tortoise His Dreams And Journeys (1964) and The Well Tuned Piano (1964) offered little or no respite for western harmony, and created a bold bridge between John Cage's "alea", Buddhist meditation and psychedelia. The former was the prototype for a special case of minimalism: droning minimalism, relying on extended (and apparently eternal) tones.

One of his disciples, Terry Riley (USA, 1935), became the guru of minimalist repetition with the pulse-based ensemble work In C (1965), that centered on the iteration of simple patterns (almost a human-based imitation of tape loops), and explored the raga-psychedelic connection with the solo electronic improvisation Rainbow in Curved Air (1968), that employed tape loop delays. These works clearly introduced repetition as a main compositional technique in western music, with (Rainbow In Curved Air) or without (In C) melody. This conceptual revolution mirrored the sociopolitical revolution of the time (the era of the "hippies"), when communal and improvised concerts prevailed over the formal presentation of classical music. Riley was emblematic of a generation of musicians who were looking for a new tonal vocabulary to express a sense of wonder. The spiritual fervor of his Persian Surgery Dervishes (1972) marked the end of the hippy-inspired era. Riley would turn to more conventional formats, but still retain the titanic urge of his minimalist years, particularly in the monumental quartets Cadenza On The Night Plain (1985) and Salome Dances For Peace (1989), and in the Requiem For Adam (1998).

The master of "slow motion music" was Steve Reich (USA, 1936), who gradually came to employ chamber ensembles and small orchestras for his masterpieces Drumming (1971), Music For 18 Musicians (1976), Music For a Large Ensemble (1978), the large-scale Desert Music (1984) and the opera The Cave (1993). His vocabulary, too, expanded over the years, as he came to favor dense textures.

Philip Glass (USA, 1937) began from similar premises but shunned Reich's austere science, and moved closer to popular music than to classical music. He moved away from the arduous repetitive patterns of Music In Twelve Parts (1974), rediscovered melody and approached the format of the opera from a different perspective with Einstein On The Beach (1976). Movie soundtracks such as Koyaanisqatsi (1983), stage operas and collaborations with pop/rock musicians became his preferred media, while his technique moved towards polytonality starting with the opera Akhnaten (1984). His most ambitious works were actually the least popular, the String Quartet 3 (1985), String Quartet 4 (1988) and String Quartet 5 (1991).

Folke Rabe (Sweden, 1935) crafted the Terry Riley-ian geometric pulsing drone music of What?? (1974).

LaMonte Young's associate Tony Conrad (USA, 1940) composed long tone pieces in just intonation for bowed strings such as Four Violins (1964).

Michael Harrison, another LaMonte Young associate, expanded Young's "well-tempered piano" to the "harmonically-tuned piano"," a customized grand piano that can alternate between two different tunings.

Starting in 1963, Stan Shaff (USA, 1929) and electrical engineer Doug McEachern crafted public three-dimensional sound events in San Francisco. In 1967 they established the sound theatre Audium, which in 1975 would move to a new location and begin offering weekly performances in complete darkness.

By the end of the 1960s a number of new musical genres and practices had pretty much developed outside and/or against the recording format. The random and indeterminate music of John Cage, the endless minimalism of LaMonte Young, the open format of free jazz, and even the live aspect of rock music were not meant to be recorded, i.e. remembered forever as performed in that one recording. Their music was a reaction to the idea of an immanence. It was meant to be transient or, at best, emergent, evolving, never completed.