Musique concrète, which means "concrete music" in French, is a type of music composition that uses recorded sounds as raw material. The technique was developed in the early 1940s by French composer Pierre Schaeffer and his associates at the Studio d’Essai of the French radio system. The fundamental principle of musique concrète lies in the assemblage of various natural sounds recorded on tape (or, originally, on disks) to produce a montage of sound. During the preparation of such a composition, the sounds selected and recorded may be modified in any way desired, such as played backward, cut short or extended, subjected to echo-chamber effects, varied in pitch and intensity, and so on. The finished composition represents the combination of varied auditory experiences into an artistic unity. The technique exploits acousmatic sound, such that sound identities can often be intentionally obscured or appear unconnected to their source cause. Musique concrète has been referred to as a sound collage technique. The theoretical basis of musique concrète as a compositional practice was developed by Schaeffer as an attempt to differentiate between music based on the abstract medium of notation and that created using so-called sound objects (lobjet sonore) .