Spatialization Paradigms

Spatialization: A Working Definition

Spatialization refers to compositional and performative practices that shape and organize the perception of sound in space.

This definition includes all conventional methods, such as mixing with artificial reverb and stereo panning. It incudes experimental methods from sound art, as well as advanced technologies like sound field synthesis. While spatialization can also include traditional aspects, such as the spatial arrangement of an orchestra, this section only deals with electronic- and computer music.

This page introduces three conceptual approaches to spatialization in electroacoustic music, sound art, and immersive media. The taxonomy presented here is not derived from technologies, formats, or rendering techniques, but based on the paradigm through which spatial structure is composed.

Channel-Based Spatialization

In channel-based spatialization, spatial structure is defined by directly shaping individual loudspeaker channels. The interaction of these channels determines the resulting spatial composition.

In its most basic form, this approach does not rely on mathematical spatial models and can be realized using elementary tools such as tape machines or analog mixing equipment. It is therefore the historically earliest concept of spatial composition and underpins quadraphonic and octophonic practices. Channel-based spatialization remains central to many traditions of acousmatic composition.

While channel-based approaches do not provide spatial authorship at the level of abstract spatial entities, they offer a high degree of practical control over the resulting spatial character. Contemporary channel-based practices often employ distributed synthesis or algorithmic processes to create spatial textures, without adhering to conventions of localization or source representation.

Because each loudspeaker signal is explicitly defined, channel-based spatialization strongly depends on a predefined playback configuration. For fixed-media works, this limits portability and complicates dissemination. At the same time, this dependence enables the use of unconventional reproduction systems and is frequently associated with site-specific works.

Object-Based Spatialization

In object-based spatialization, sound sources are treated as discrete entities positioned in space, often referred to as virtual sound sources. Spatial structure is defined through the arrangement of these sources and their relations in space.

In composition and performance, spatial aspects are specified by controlling source positions directly or by defining trajectories that describe their evolution over time. Spatial intent is formulated independently of the loudspeaker system and rendered at playback time. This separation makes object-based approaches largely system-agnostic and facilitates the transfer of spatial concepts between different reproduction configurations.

Object-based spatialization lends itself to the construction of virtual acoustic scenes, in which multiple sound sources are perceptually integrated within a shared spatial and acoustic frame. However, object-based approaches do not necessarily imply scene-based thinking; they are equally applicable to abstract or non-representational spatial compositions.

The object-based concept is foundational in many interactive and adaptive contexts, including game audio, virtual environments, and contemporary spatial music practices. Accordingly, a wide range of professional hardware and software systems support object-based spatialization workflows.

Field-Based Spatialization

In field-based spatialization, space itself becomes the compositional medium. Spatial structure is not described in terms of discrete sound sources or loudspeaker channels, but through the manipulation of an explicit spatial sound field.

While technically a narrow and comparatively rare approach, field-based spatialization is conceptually distinct from both channel-based and source-based paradigms. Its defining feature is that spatial form emerges from field properties rather than from the placement or movement of sound objects.

The field-based concept is characterized by the absence of identifiable sound sources. Spatial structure is defined directly at the level of the field representation, and transformations are applied to this representation as a whole. As with source-based approaches, spatial intent is specified independently of the reproduction system and rendered at playback time.

Aesthetically, field-based spatialization often aligns more closely with channel-based traditions than with source-based ones, particularly in its emphasis on diffuse spatial distributions, non-causal space, and experimental shaping of spatial sound textures.

Technologies and Hybrid Practices

Many spatial audio technologies can realize multiple concepts, depending on compositional intent:

• Ambisonics may support source-based or field-based practices.

• Fixed multichannel systems may host channel-based or rendered object-based work.

• Diffusion can reinterpret material composed under any concept.