Ambisonic Source

An AmbisonicSource renders an already encoded first-order Ambisonic sound field. It matches Steam Audio’s Unity Ambisonic Source behavior: the input is AmbiX (ACN/SN3D), the source orientation rotates the sound field, and the output is stereo.

Ambisonic sources are independent of point sources. They do not use position, distance attenuation, occlusion, reflections, reverb, or WorldOptions.maxSources.

Creating an Ambisonic source

const source = world.createAmbisonicSource({
  binaural: true,
})
const node = world.createAmbisonicNode(source)

ambisonicInput.connect(node)
node.connect(world.audioContext.destination)

The input must contain exactly four discrete channels: first-order AmbiX using ACN channel ordering and SN3D normalization. The node uses channelCountMode: 'explicit' and channelInterpretation: 'discrete' to preserve the Ambisonic channels.

setOrientation(orientation)

source.setOrientation(object.quaternion)

Sets the orientation of the sound field. The source position is intentionally not part of this interface. The listener orientation comes from world.listener.

setBinaural(enabled)

source.setBinaural(false)

Enables or disables HRTF-based rendering. It defaults to true. When disabled, Steam Audio still decodes the Ambisonic field to the stereo speaker layout; it does not pass the four input channels through unchanged.

dispose()

Releases the source and all nodes created for it.

SteamAudioAmbisonicNode

SteamAudioAmbisonicNode is created by world.createAmbisonicNode(source). It is a standard Web Audio AudioNode with one input and one stereo output.

It exposes the same lifecycle properties as SteamAudioNode:

• ready: Promise<void>
• state: 'initializing' | 'ready' | 'failed' | 'disposed'
• error: Error | undefined
• dispose(): void

An input with any channel count other than four causes the node to enter the failed state and emit silence.