Acousmatic music is a specialised sub-set of
electroacoustic music. It is created using non-
acoustic technology, exists only in recorded form in a fixed medium, and is
composed specifically to be heard over
loudspeakers. The musical material is not restricted to the sounds of
musical instruments or
voices, nor to elements traditionally thought of as 'musical' (
melody,
harmony, metrical
rhythms, and so on), but rather admits any
sound, acoustic or
synthetic, and any way of combining or juxtaposing sounds, as potentially musical.
The term acousmatique was first used by the French composer
Pierre Schaeffer, in his book Traité des Objets Musicaux (1966). It is said to be derived from akusmatikoi, the outer circle of
Pythagoras' disciples who only heard their teacher speaking from behind a veil. In a similar way, one hears acousmatic music from behind the 'veil' of
loudspeakers, without seeing the source of the sound.
Acousmatic composers use this invisibility of sound sources as a positive aspect of the creative process, in one of two ways. The first is to separate the listener from the visual and physical context of the sounds being used, in order to permit a more concentrated and
abstract form of listening unencumbered by the real-world associations or 'meaning' of the sounds. This form of listening is known as reduced listening (Schaeffer), and it allows both acoustic and
synthetic sounds to be used to create an abstract musical discourse the focus of which is the detail of individual sounds, and the
evolution and interaction of these sounds. The second approach is to deliberately evoke real-world associations by using identifiable sounds (real world objects, voices, environments) to create
mental images in sound.
Although these two contrasting approaches are in some ways diametrically opposed, they may nevertheless be combined in order to exploit the tension that exists between them.