---
title: PHASEEnvelopeDistanceModelParameters
framework: phase
role: symbol
role_heading: Class
path: phase/phaseenvelopedistancemodelparameters
---

# PHASEEnvelopeDistanceModelParameters

A graph of points and curves that shapes the volume of a sound over distance.

## Declaration

```swift
class PHASEEnvelopeDistanceModelParameters
```

## Overview

Overview This class provides an envelope that the app configures to dissipate the volume of a source’s sound with distance. The envelope describes a graph that the app configures using points and curves, where the input value is the distance between a sound source and the listener, and the output value is the sound’s volume. Dissipate Sound by Using an Envelope The framework interprets this class’s envelope as a gain curve, which determines the sound’s volume over a distance. An envelope offers more precise control over sound dissipation than a geometric rolloffFactor. For example, the following code defines slow sound dissipation followed by a sharp decrease:

## Topics

### Creating the Distance Model Parameters

- [init(envelope:)](phase/phaseenvelopedistancemodelparameters/init(envelope:).md)

### Shaping the Volume Over a Distance

- [envelope](phase/phaseenvelopedistancemodelparameters/envelope.md)

## Relationships

### Inherits From

- [PHASEDistanceModelParameters](phase/phasedistancemodelparameters.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)
- [PHASEDistanceModelFadeOutParameters](phase/phasedistancemodelfadeoutparameters.md)
- [PHASEDistanceModelParameters](phase/phasedistancemodelparameters.md)