Music concrête is a type of music that sprang directly out of the evolution of music technology. As a throwback to classical music being inspired by poetic forms, music concrête has its roots in the 1920s Surrealist literary practice of cut-up and fold-in composition.
In cut-up, writers would physically cut up existing pieces of literature and rearrange the order of the phrases and words, whereas in fold-in compositions, a group of writers would write random phrases, one at a time, on a piece of paper, folding the paper over after each turn so that the next writer couldn't see what the previous writer had written. In the 1930s, French composer Pierre Schaeffer began experimenting with splicing bits of analog tape together to create music completely different from the source material.
Music concrête basically means that you make music out of existing sounds. This can range from human voices (as in Steve Reich's "It's Gonna Rain" and "Come Out"), spinning around on a radio dial (Ben Azarm's "Neoapplictana"), static (Apollon and Muslimgauze's "Year Zero"), or a combination of power tools and bird songs (such as in the music of Japanese noise rocker Rhizome). A list of significant pioneers of the music concrête movement must include Swiss musician Christian Marclay, whose most notorious composition, 1988's "Footsteps," was created by having thousands of people walk across many copies of the same slab of vinyl and then playing the damaged records on a turntable, recording the best bits for an album under the same title.
Throughout the 1980s, rap artists used the ideas behind music concrête to completely change the way contemporary pop musicians would create music. Through their use of samples and loops of existing music and dialog, artists such as Del Tha Funky Homo Sapien and Ice T brought music concrête from art galleries and other experimental music forums into the forefront of popular music.