L'Acousmonium is the sound diffusion system designed by Francois Bayle and used by the Groupe de Recherches Musicales at the Maison de Radio France. To quote a CD sleeve note:
Espace de Projection - the auditorium at IRCAM opened in 1978. Its acoustical properties can be changed to provide the best conditions for recordings or public performances. As you would expect, it has been used for the first performances of many works created at IRCAM, and many recordings made by the Ensemble InterContemperain have been made here too.
L'Acousmonium is the sound diffusion system designed by Francois Bayle and used by the Groupe de Recherches Musicales at the Maison de Radio France. To quote a CD sleeve note:
Another utopia, devoted to pure "listening": the Acousmonium, designed in the early '70s (20 years already!) as a penetrable "projection area", arranged with a view to immersion in sound, to spatialised polyphony, which is articulated and directed.
Poullin's Potentiometre d'Espace. This was used for the first ever public performance of musique concrète in the hall of the École Normale de Musique, Paris on 18 March 1950. The main work performed was Symphonie pour un Homme Seul.
It consisted of four loudspeakers - three located in a triangle around the audience and one in the ceiling. Five tape tracks were used - four were connected directly to the loudspeakers, but the fifth track was connected to a hand-held transmitting coil held by the 'performer' who stood inside a tetrahedron of receiving coils reproducing in miniature the position of the loudspeakers in the hall. By moving the transmitting coil around, the performer could 'steer' the apparent position of sounds on the fifth channel around the hall.