Editing Musique concrète (section)

===Initial tools of musique concrète===
In 1948, a typical [[radio studio]] consisted of a series of shellac [[phonograph|record players]], a [[shellac]] record recorder, a [[mixing desk]] with rotating [[potentiometer]]s, mechanical [[reverberation]] units, [[audio filter|filters]], and [[microphone]]s. This technology made a number of limited operations available to a composer:<ref name="Teruggi-2007-pneeded">{{harvp|Teruggi|2007}}{{Page needed|date=September 2014}}</ref>
*'''Shellac record players''': could play sound forwards or in reverse; could change speed at fixed ratios, permitting limited [[Transposition (music)|transposition]].
*'''Shellac recorder''': would record any result coming out of the mixing desk.
*'''Mixing desk''': would permit several sources to be mixed together with an independent control of the gain or volume of the sound. The result of the mixing was sent to the recorder and to the monitoring loudspeakers. Signals could be sent to the filters or the reverberation unit.
*'''Mechanical reverberation''': made of a metal plate or a series of springs that created an artificial reverb effect.
*'''Filters''': two kinds of filters, third-octave octave filter banks and [[high-pass filter|high-]] and [[low-pass filter]]s. They allowed the elimination or enhancement of selected [[audio frequency|frequencies]].
*'''Microphones''': essential tool for capturing sound.

The application of the above technologies in the creation of musique concrète led to the development of a number of sound manipulation techniques including:<ref name="Teruggi-2007-pneeded"/>

*'''Sound transposition''': reading a sound at a different speed than the one at which it was recorded.
*'''Sound looping''': composers developed a skilled technique in order to create loops at specific locations within a recording.
*'''Sound-sample extraction''': a hand-controlled method that required delicate manipulation to get a clean [[Sampling (music)|sample]] of sound. It entailed letting the [[Magnetic cartridge|stylus]] read only a small segment of a [[phonograph|record]]. Used in the ''Symphonie pour un homme seul''.
*'''Filtering''': by eliminating certain frequencies from a signal, the remains would keep some trace of the original sound but alter it often beyond recognition.