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# PHASEMetaParameter

A named parameter with a value that the app can change over time.

```
class PHASEMetaParameter
```

## Overview

Instances of this class provide an app with dynamic control of a sound’s properties. A metaparameter takes a single value as input and may operate on one or more audio characteristics.

To change the value of a metaparameter at runtime:

- Assign a string to a textual metaparameter’s [`value`](/documentation/PHASE/PHASEMetaParameter/value).
- Adjust the value of a number or mapped metaparameter gradually over a duration by calling [`fade(value:duration:)`](/documentation/PHASE/PHASENumberMetaParameter/fade(value:duration:)).

## Topics

### Accessing the Value

[`value`](/documentation/PHASE/PHASEMetaParameter/value)

A value for the metaparameter.

### Identifying the Parameter

[`identifier`](/documentation/PHASE/PHASEMetaParameter/identifier)

A unique name for the metaparameter.

## Relationships

### Inherited By

[`PHASEStringMetaParameter`](/documentation/PHASE/PHASEStringMetaParameter)

[`PHASENumberMetaParameter`](/documentation/PHASE/PHASENumberMetaParameter)

### Conforms To

[`CustomStringConvertible`](/documentation/Swift/CustomStringConvertible)

[`NSObjectProtocol`](/documentation/ObjectiveC/NSObjectProtocol)

[`CustomDebugStringConvertible`](/documentation/Swift/CustomDebugStringConvertible)

[`Equatable`](/documentation/Swift/Equatable)

[`Hashable`](/documentation/Swift/Hashable)

[`CVarArg`](/documentation/Swift/CVarArg)

### Inherits From

[`NSObject-swift.class`](/documentation/ObjectiveC/NSObject-swift.class)

---

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