The Late 20th Century era

Composers of this era sought to free music from its rigidity, placing the performance above the composition. Similarly, many composers sought to break from traditional performance rituals by incorporating theatre and multimedia into their compositions, going beyond sound itself to achieve their artistic goals. In some cases the line is difficult to draw between genres.

Composers were quick to adopt developing electronic technology. As early as the 1940s, composers such as Olivier Messiaen incorporated electronic instruments into live performance. Recording technology was used to produce art music, as well.

The musique concrète of the late 1940s and ’50s was produced by editing together natural and industrial sounds. Steve Reich created music by manipulating tape recordings of people speaking, and later went on to compose process music for traditional instruments based on such recordings. Other notable pioneers of electronic music include Edgard Varèse, Karlheinz Stockhausen, Luigi Nono, and Krzysztof Penderecki.

As more electronic technology matured, so did the music. In the 1950s aleatoric music was first championed by American composer John Cage. Early minimalist compositions of the 1960s such as those by Terry Riley, Steve Reich, and Philip Glass stemmed from aleatoric and electronic music.