 Access to microphones, phonographs, and later magnetic tape recorders (created in 1939 and acquired by the Schaeffer's Groupe de Recherche de Musique Concrète (Research Group on Concrete Music) in 1952), facilitated by an association with the French national broadcasting organization, at that time the Radiodiffusion-Télévision Française, gave Schaeffer and his colleagues an opportunity to experiment with recording technology and tape manipulation.In 1948, a typical radio studio consisted of a series of shellac record players, a shellac record recorder, a mixing desk with rotating potentiometers, mechanical reverberation, filters, and microphones.This technology made a number of limited operations available to a composer (, )