Adding audio components in Reality Composer Pro
Configure audio components in a Reality Composer Pro scene.
Overview
Reality Composer Pro provides a set of audio components you can add to entities in your scene to control how sound is rendered. The three main audio source components — Spatial Audio, Ambient Audio, and Channel Audio — differ in how they respond to listener position and orientation.
A Reverb component lets you define an environment-wide reverb preset. Audio File Groups and the Audio Library Component provide flexible ways to reference and play audio assets from within your scene’s logic. An Audio Mix Group lets you control the volume and playback speed of a collection of sounds together through a single slider.
Import audio files through the Project Browser
In the Project Browser, click Import Asset, select one or more audio files, and then click Open. Alternatively, drag files from the Finder into the desired location in the Project Browser.
Inspect and preview audio
To play back an audio file from the Project Browser, click an audio file. In the Preview tab, click Play.
The Inspector displays the following basic audio properties for the file.
Should Loop — When toggled on, the audio loops seamlessly. If you attempt to loop the sound using the completionHandler in the API, there will be a slight gap between repeats. Configuring the looping behavior on the resource allows the audio engine to guarantee sample-precise seamless looping.
Should Randomize Start — Randomizes the start time of the audio file.
Use Should Randomize Start and Should Loop together to create audio variation using the same audio file. This is useful when you want constant sound with subtle variation, such as ambient nature sounds.
Should Stream — When toggled on, the audio streams from disk instead of loading into memory.
Streaming audio saves memory but uses more compute. For more information, see AudioFileResource.LoadingStrategy.
Choose an audio playback component
There are three main audio components you can add to control how audio is rendered in space within your scene. Use Spatial Audio when sound should emanate from a specific entity and respond to your environment’s reverb. Use Ambient Audio for multichannel recordings where orientation matters but position does not. Use Channel Audio for music or non-spatialized audio that routes directly to device output channels.
Add a Spatial Audio component
Spatial Audio is the default audio component placed on an entity. If you don’t specify Ambient or Channel for an entity, the system renders audio as Spatial.
Spatial audio emanates from its entity.
Spatial Audio inherits reverberation characteristics of the environment.
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For more information, see SpatialAudioComponent.
Add an Ambient Audio component
Ambient Audio renders each channel of an audio resource from an angle based on the entity’s orientation. As you move toward or away from the entity, the volume does not change. As the entity or listener rotates, the audio channels shift accordingly. This makes Ambient Audio well-suited for multichannel field recordings of outdoor environments.
Ambient audio is position-independent but orientation-sensitive.
Ambient Audio does not take on Reverb characteristics; it relies on Reverb effects recorded in the source audio file.
For more information, see AmbientAudioComponent.
Add a Channel Audio component
Channel Audio routes audio directly to the device output channels with no spatialization or reverberation applied. Neither the entity’s position nor its orientation affects playback — the left channel always plays from the left and the right channel always from the right, regardless of listener orientation.
Channel Audio does not take on Reverb characteristics.
Channel Audio is typically used for music.
For more information, see ChannelAudioComponent.
Add a Reverb component
Add a Reverb component to an entity to define a preset Reverb characteristic such as Living Room or Concert Hall for a scene.
Only one Reverb component can be active at a time in a scene, and you can place it anywhere in a scene.
For more information, see ReverbComponent.
Add an Audio File Group to your project
Add an Audio File Group to define a collection of audio files. When RealityKit plays an Audio File Group, it selects a random file from the collection — useful for groups of similar but varied sounds, such as footsteps or bird calls. You reference Audio File Groups through an Audio Library Component attached to an entity.
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You can have as many Audio File Groups in your project as you need. For example, you might define a group for Forest Sounds and another for Musical Instrument Sounds.
In the Project Browser, click [+], then click Audio > Audio File Group**.
Type a name for the Audio File Group and press Return.
Click your Audio File Group.
In the Inspector, under Audio File Asset, next to Sound, click the field and select an audio file from your project.
To add more files to the Audio File Group, click + next to Assets.
After creating an Audio File Group, add an Audio Library Component to an entity and connect the component to the Audio File Group.
Add an Audio Library Component to an entity
The Audio Library Component lets you reference and play specific sounds directly, or reference an Audio File Group to play sounds selected at random. Other components, such as Script Graphs and Animation Sequences, can reference audio files in the library.
Select an entity in your project.
In the Inspector, click Add Component > Audio Library.
Click +Named Audio Reference.
Next to Name, type a name for the audio asset.
Click the Audio Asset field and select an audio file from the list.
Repeat the last two steps to add as many audio references as you need.
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For more information, see AudioLibraryComponent.
Add an Audio Mix Group component
Use an Audio Mix Group to group sounds together — for example, instruments in a band, voices, and other environmental sounds — and then control their volume and playback speed as a group through a single slider. Add only one Audio Mix Group to your scene.
In the Project Browser, click [+] > Audio > Audio Mix Group.
Type a name for the Mix Group and then press Return.
In the Inspector, under Sounds, click Add Sound and select a sound.
Repeat the previous step to add more sounds to the Mix Group.