Editing Musique concrète (section)

====Early sound spatialisation system====
[[File:Pierre Henry in concert, 1952.jpg|thumb|right|[[Pierre Henry]] using induction coils to control sound spatially]]
At the premiere of Pierre Schaeffer's ''Symphonie pour un homme seul'' in 1951, a system that was designed for the spatial control of sound was tested. It was called a ''relief desk'' (''pupitre de relief'', but also referred to as ''pupitre d'espace'' or ''potentiomètre d'espace'') and was intended to control the dynamic level of music played from several shellac players. This created a [[stereophonic]] effect by controlling the positioning of a [[monaural|monophonic]] sound source.<ref name="Teruggi-2007-p218"/> One of five tracks, provided by a purpose-built tape machine, was controlled by the performer and the other four tracks each supplied a single loudspeaker. This provided a mixture of live and preset sound positions.<ref>{{harvp|Poullin|1957}}</ref> The placement of loudspeakers in the performance space included two loudspeakers at the front right and left of the audience, one placed at the rear, and in the centre of the space a loudspeaker was placed in a high position above the audience. The sounds could therefore be moved around the audience, rather than just across the front stage. On stage, the control system allowed a performer to position a sound either to the left or right, above or behind the audience, simply by moving a small, hand held transmitter coil towards or away from four somewhat larger receiver coils arranged around the performer in a manner reflecting the loudspeaker positions.<ref name="Teruggi-2007-p218"/> A contemporary eyewitness described the ''potentiomètre d'espace'' in normal use:

<blockquote>One found one's self sitting in a small studio which was equipped with four loudspeakers—two in front of one—right and left; one behind one and a fourth suspended above. In the front center were four large loops and an ''executant'' moving a small magnetic unit through the air. The four loops controlled the four speakers, and while all four were giving off sounds all the time, the distance of the unit from the loops determined the volume of sound sent out from each.<br>The music thus came to one at varying intensity from various parts of the room, and this ''spatial projection'' gave new sense to the rather abstract sequence of sound originally recorded.<ref>{{harvp|Gradenwitz|1953}}</ref></blockquote> The central concept underlying this method was the notion that music should be controlled during public presentation in order to create a performance situation; an attitude that has stayed with acousmatic music to the present day.<ref name="Teruggi-2007-p218"/>