A Pythagorian term reintroduced in 1955 by Jérôme Peignot which considers the "distance which separates sounds from their origin", i.e., an audio-only presentation of sound common to electroacoustic music.
For some, the term is very precise and refers specifically to this listening situation. However, the term has gained wider usage, in describing a genre, which, to a large extent derives from the Musique Concrète tradition and is founded upon this listening situation.