---
title: AudioMixGroupsComponent
framework: realitykit
role: symbol
role_heading: Structure
path: realitykit/audiomixgroupscomponent
---

# AudioMixGroupsComponent

A component that provides functionality for controlling the playback of audio you assign to mix groups in a scene.

## Declaration

```swift
struct AudioMixGroupsComponent
```

## Overview

Overview When defining an AudioMixGroup for a scene in the Audio Mixer section of Reality Composer Pro, this component exists on the first descendant Entity in the scene at runtime. A common use case for AudioMixGroupsComponent is to simultaneously control the playback volume of every AudioResource in an AudioMixGroup, such as the sound effects in a scene. The following example sets the playback volume of every AudioResource in the AudioMixGroup named SFX: let sceneEntity = Entity(named: "ContainsAudio", in: realityKitContentBundle)

// AudioMixGroupsComponent exists on the first descendant Entity in a scene. var audioMixGroupsEntity = sceneEntity.children[0]

// If no audio mix groups are configured for this scene in Reality Composer Pro, this component won't exist. guard var audioMixGroupsComponent = audioMixGroupsEntity.components[AudioMixGroupsComponent.self],      var sfxGroup = audioMixGroupsComponent.mixGroup(named: "SFX") else {     return }

// This code remaps a percent value between 0 and 100 to a decibel value between -60.0 and 0.0. // Because -60.0 dB is near the low-end of human hearing ability, this is a good value to use in this example. let volumePercent: Float = 50 let decibels = Audio.Decibel(-40.0 + (20 * log10(volumePercent)))

// Control the playback volume with the gain property on an AudioMixGroup. sfxGroup.gain = decibels

audioMixGroupsComponent.set(sfxGroup) audioMixGroupsEntity.components.set(audioMixGroupsComponent) To completely silence an AudioMixGroup, use the isMuted property. Use fade(to:duration:) to fade the volume of an AudioMixGroup over time.

## Topics

### Initializers

- [init(mixGroups:)](realitykit/audiomixgroupscomponent/init(mixgroups:).md)

### Instance Methods

- [mixGroup(named:)](realitykit/audiomixgroupscomponent/mixgroup(named:).md)
- [remove(named:)](realitykit/audiomixgroupscomponent/remove(named:).md)
- [set(_:)](realitykit/audiomixgroupscomponent/set(_:).md)

## Relationships

### Conforms To

- [Component](realitykit/component.md)
- [Copyable](swift/copyable.md)
- [Equatable](swift/equatable.md)
- [Escapable](swift/escapable.md)
- [Hashable](swift/hashable.md)

## See Also

### Audio mixing

- [Mixing spatial music](realitykit/mixing-spatial-music.md)
- [AudioMixGroup](realitykit/audiomixgroup.md)