Electroacoustic & Acousmatic Music
- Acousmatic music has treated space as material the longest — everything is fixed on a support in the studio.
- Compose the space in; do not leave it to the diffusion to add.
- Diffusion re-projects a fixed work over a loudspeaker orchestra, live — a genuine performance (Acousmonium, BEAST).
- The same material can become a concert or an installation — opposite audience relationships.
Acousmatic music is the practice in which space has been treated as compositional material the longest, and where the artistic vocabulary for spatialisation is richest. It is worth understanding on its own terms even if you work in other domains, because almost every idea in the rest of this part was first worked out here.
The word acousmatic names a way of listening: to sound whose source is hidden, so that you attend to the sound itself rather than to what produced it. The term was revived by the poet Jérôme Peignot in 1955 and made into a musical genre by François Bayle around 1974, but the practice begins earlier, with Pierre Schaeffer's musique concrète at the French radio in 1948 and the founding of the studio that became the Groupe de Recherches Musicales (GRM) in 1958. From the start this was music fixed on a support — tape, then disk, then file — and therein lies both its freedom and its central problem.
The fixed-support condition
An acousmatic work has no live players. Everything — timbre, gesture, and crucially space — is composed and fixed in the studio. This is a profound freedom: you can place a sound anywhere, move it along any trajectory, give it any distance or reverberation, with a precision no ensemble of musicians could match. The composed space (see Thinking the Sound Space) can be built to the finest detail.
But a fixed support meets a variable world. The piece will be played in rooms of different sizes and acoustics, over loudspeaker systems from a modest stereo pair to an orchestra of a hundred speakers. The composed space is settled; the listening space is not. Bridging that gap is not an afterthought in acousmatic practice — it is a second act of composition, performed in the room. This is diffusion.
Composing space from the studio outward
Because there are no players, the discipline is to compose spatial intention into the work while still in the studio, in a way that will survive diffusion. Two bodies of thought help.
Pierre Schaeffer's theory of the sound object (the Traité des objets musicaux, 1966, made accessible in Michel Chion's Guide des objets sonores, 1983) trains you to hear and shape sound as material independent of its cause — the prerequisite for treating its space as material too. Denis Smalley's spectromorphology (Organised Sound, 1997) gives the vocabulary for how sound-shapes move and transform, and his later "Space-form and the acousmatic image" (2007) extends it explicitly to space — the composed space / listening space distinction, the figure/ground of perspectival space, the typed spatial gestures — that underpins the whole Thinking the Sound Space chapter. Smalley's own works are unusually legible case studies: the opening of Empty Vessels (1997) as a textbook "opening" of perspectival space, Base Metals (2000) for spectral space and gravitation, Valley Flow (1992) for the "presence" of a space created by continuous planes without any identifiable motion.
The practical instruction is: do not leave space to the diffusion. Build distance, width, envelopment and gesture into the fixed work as material, so that diffusion interprets an already-spatial piece rather than trying to manufacture space that was never composed. Robert Normandeau states the principle bluntly: space "is not a conception that is added at the end… but is a real, composed spatialization" — his practice of timbre spatialisation, fragmenting a sound's spectrum across diffusion points so it only recomposes in the room, is decided when composing the material itself, not applied to a finished mix.
The diffusion performance
Diffusion is the acousmatic answer to the sweet-spot problem, and it turns delivery into performance. The lineage is traced in Diffusion Logics: the pupitre d'espace of 1951, Clozier's Gmebaphone at Bourges (1973) and Bayle's Acousmonium of 1974 — rival "orchestras of loudspeakers," one diffusing by filtered spectrum, the other by level — and Britain's BEAST from 1982, which builds arrays of up to a hundred speakers and treats diffusion as near-improvised interpretation.
What the diffuser actually does, at the mixing desk during the concert:
- Re-orchestrates for the room. A stereo (or few-channel) fixed work is spread live across the array — sending material to near or distant speakers, to the sides, overhead — so that the composed space is re-projected into this hall, compensating for its size and acoustics. The same piece is diffused differently in a dry studio and a resonant church.
- Performs the dynamics of space. Movements are played by hand, shaped to the room and the moment — a swell pushed outward to the far speakers, an intimate passage pulled to the front pair. This is genuinely interpretive; two diffusers give two different performances of the same fixed file, and Jonty Harrison and Annette Vande Gorne both write about it as a real performance practice ("Sound, Space, Sculpture," 1998; "L'interprétation spatiale," 2002).
- Prepares a diffusion score. For a serious concert the diffuser rehearses in the hall and notes a plan — which passages go where, where the array is engaged, where to hold back — a score for the performance of space that is separate from the piece itself.
This is worth internalising even outside acousmatic music: it is the clearest existing model of diffusion as interpretation rather than setting, and modern tools generalise it. Live control from a tablet during the show is the direct descendant of the diffuser's desk; timeline automation of spatial parameters (the RIPL timeline treats position as an automatable parameter like any fader) lets the same interpretive shaping be composed in advance and recalled exactly, or performed live, or both.
From concert to installation
Not all acousmatic-adjacent work is a concert. The same fixed-support material can be deployed as a permanent or long-running installation, which changes the audience relationship entirely — from a gathered, simultaneous audience facing an array to individuals who arrive, move and leave. Max Neuhaus's insistence on the place (an unbounded, discovered sound-work) over the concert (a bounded, framed event), and Cardiff & Bures Miller's The Forty Part Motet (forty voices, forty loudspeakers, the audience walking among them), are the reference points; both are discussed in Diffusion Logics. The compositional question shifts from how does this unfold in time for a seated audience to how does this reward a listener who composes their own path and duration through it.
Common decisions and pitfalls
- Compose the space, don't outsource it. A work that arrives at the concert spatially flat, hoping the diffuser will "add space," gives the diffuser nothing to interpret. Build the space in.
- Know your delivery: concert or installation. They demand opposite temporal strategies — a directed unfolding versus a rewarding wander.
- Rehearse the diffusion in the actual hall. The composed space and the listening space only meet in the room; a diffusion designed on studio monitors is a guess.
- Respect perceptible density. The studio tempts you to stack more simultaneous spatial voices than any hall will let a listener follow; the fixed support makes it permanent. Budget the density (see Thinking the Sound Space).
- Beware the imperceptible. Fixed-support precision invites motion too subtle to survive a real room and a real audience. If a gesture matters, make it legible from more than the centre seat.
Bibliography
- Bayle, François. Musique acousmatique : propositions… …positions. Paris: INA / Buchet-Chastel, 1993.
- Chion, Michel. Guide des objets sonores : Pierre Schaeffer et la recherche musicale. Paris: INA / Buchet-Chastel, 1983.
- Chion, Michel. L'art des sons fixés. Fontaine: Metamkine / Nota Bene / Sono-Concept, 1991.
- Gayou, Évelyne. GRM — Le Groupe de Recherches Musicales, cinquante ans d'histoire. Paris: Fayard, 2007.
- Harrison, Jonty. "Sound, Space, Sculpture: Some Thoughts on the 'What,' 'How' and 'Why' of Sound Diffusion." Organised Sound 3, no. 2 (1998): 117–127.
- Normandeau, Robert. "Timbre Spatialisation: The Medium is the Space." Organised Sound 14, no. 3 (2009): 277–285.
- Schaeffer, Pierre. Traité des objets musicaux. Paris: Seuil, 1966.
- Smalley, Denis. "Spectromorphology: explaining sound-shapes." Organised Sound 2, no. 2 (1997): 107–126.
- Smalley, Denis. "Space-form and the acousmatic image." Organised Sound 12, no. 1 (2007): 35–58.
- Vande Gorne, Annette. "L'interprétation spatiale. Essai de formalisation méthodologique." Revue DÉMéter, 2002.
A note on sourcing: the historical account above (dates of the GRM, the Acousmonium, the coining of "acousmatic") follows widely-corroborated sources; a few exact dates vary slightly between them and are worth confirming before print.