For the purposes of the Subject Index, all terminology created by the French theorist Pierre Schaeffer in his phenomenologically inspired researches into the experience, perception and classification of sound, music technology, and composition of musique concrète can be found under this umbrella term.
All terms currently featured in the Glossary and Subject Index can be found in Schaeffer's seminal text, Traité des objets musicaux, Éditions du Seuil, 1966.