---
title: PHASENumberMetaParameter
framework: phase
role: symbol
role_heading: Class
path: phase/phasenumbermetaparameter
---

# PHASENumberMetaParameter

A metaparameter defined by a number that can change over time.

## Declaration

```swift
class PHASENumberMetaParameter
```

## Overview

Overview This class contains a number that updates, like a “player speed” metaparameter that the app changes gradually from 0.0 to 1.0. To create an instance of this class, first create a PHASENumberMetaParameterDefinition, and either: Register it with the engine by calling registerGlobalMetaParameter(metaParameterDefinition:), then access the instance of this class in the engine’s globalMetaParameters dictionary. Pass it to the PHASEBlendNodeDefinition initializer, init(blendMetaParameterDefinition:identifier:), and then access the instance of this class in a sound event’s metaParameters dictionary. Use it as the input value for a PHASEMappedMetaParameterDefinition by passing it into the init(inputMetaParameterDefinition:envelope:) initializer. Then, access the instance of this class using the mapped parameter’s inputMetaParameterDefinition property.

## Topics

### Inspecting Extremes

- [minimum](phase/phasenumbermetaparameter/minimum.md)
- [maximum](phase/phasenumbermetaparameter/maximum.md)

### Interpolating the Value

- [fade(value:duration:)](phase/phasenumbermetaparameter/fade(value:duration:).md)

## Relationships

### Inherits From

- [PHASEMetaParameter](phase/phasemetaparameter.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

### Linear Metaparameters

- [PHASENumberMetaParameterDefinition](phase/phasenumbermetaparameterdefinition.md)