---
title: PHASESpatialMixerDefinition
framework: phase
role: symbol
role_heading: Class
path: phase/phasespatialmixerdefinition
---

# PHASESpatialMixerDefinition

An audio-layering object that produces environmental effects and plays sound with a 3D position and orientation.

## Declaration

```swift
class PHASESpatialMixerDefinition
```

## Mentioned in

Playing sound from a location in a 3D scene

## Overview

Overview This class enables the app to define a relationship between a source and listener in six degrees of freedom: orientation (roll, pitch, yaw) and a 3D position (x, y, z). The framework plays back an audio source with distance modeling (see distanceModelParameters), direct path transmission effects and any combination of environmental effects, such as reverb (see PHASESpatialPipeline), and directivity (see listenerDirectivityModelParameters).  The result enables an app to implement directive point or omnidirectional sound sources — with or without direction, respectively — and volumetric sources with a defined shape. For a walkthrough of spatial mixing, see Playing sound from a location in a 3D scene.

## Topics

### Creating a Spatial Mixer

- [init(spatialPipeline:)](phase/phasespatialmixerdefinition/init(spatialpipeline:).md)
- [init(spatialPipeline:identifier:)](phase/phasespatialmixerdefinition/init(spatialpipeline:identifier:).md)

### Setting a Pipeline

- [spatialPipeline](phase/phasespatialmixerdefinition/spatialpipeline.md)

### Changing Sound Over Distance

- [distanceModelParameters](phase/phasespatialmixerdefinition/distancemodelparameters.md)

### Configuring Directivity

- [listenerDirectivityModelParameters](phase/phasespatialmixerdefinition/listenerdirectivitymodelparameters.md)
- [sourceDirectivityModelParameters](phase/phasespatialmixerdefinition/sourcedirectivitymodelparameters.md)

## Relationships

### Inherits From

- [PHASEMixerDefinition](phase/phasemixerdefinition.md)

### Conforms To

- [CVarArg](swift/cvararg.md)
- [CustomDebugStringConvertible](swift/customdebugstringconvertible.md)
- [CustomStringConvertible](swift/customstringconvertible.md)
- [Equatable](swift/equatable.md)
- [Hashable](swift/hashable.md)
- [NSObjectProtocol](objectivec/nsobjectprotocol.md)