---
title: PHASEDistanceModelParameters
framework: phase
role: symbol
role_heading: Class
path: phase/phasedistancemodelparameters
---

# PHASEDistanceModelParameters

A base class for a sound’s rate of change over distance.

## Declaration

```swift
class PHASEDistanceModelParameters
```

## Overview

Overview When your app outputs sound with a 3D position and orientation, designate a subclass of this class to indicate the manner in which PHASE changes sound with distance. Assign an instance of either PHASEGeometricSpreadingDistanceModelParameters or PHASEEnvelopeDistanceModelParameters, depending on your app’s needs, to the PHASESpatialMixerDefinition class’s distanceModelParameters property.

## Topics

### Fading the Sound

- [fadeOutParameters](phase/phasedistancemodelparameters/fadeoutparameters.md)

## Relationships

### Inherits From

- [NSObject](objectivec/nsobject-swift.class.md)

### Inherited By

- [PHASEEnvelopeDistanceModelParameters](phase/phaseenvelopedistancemodelparameters.md)
- [PHASEGeometricSpreadingDistanceModelParameters](phase/phasegeometricspreadingdistancemodelparameters.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)

## See Also

### Distance Modeling

- [PHASEGeometricSpreadingDistanceModelParameters](phase/phasegeometricspreadingdistancemodelparameters.md)
- [PHASEEnvelopeDistanceModelParameters](phase/phaseenvelopedistancemodelparameters.md)
- [PHASEDistanceModelFadeOutParameters](phase/phasedistancemodelfadeoutparameters.md)