Its basic idea is to replace the traditional material of music (acoustic instrumental and vocal sounds) with recorded sounds obtained from many different sources, such as noises, voice, percussion, and others. As a rule this material is subjected to various modifications by mechanical and electronic means. The montage of sounds is then presented in its final form as a single or multi-track recording, thus eliminating the live performer and the need for a score.
It was Schaeffer who named this development "musique concrete," i.e., music made directly on tape with real sounds, as opposed to "musique abstraite," where the sounds are notes (pitch abstractions) composed into an abstract system of signs (score).
(see also Electronic Music)