<!--
{
  "availability" : [
    "iOS: 9.0.0 -",
    "iPadOS: 9.0.0 -",
    "macCatalyst: 13.1.0 -",
    "macOS: 10.11.0 -",
    "tvOS: 9.0.0 -",
    "visionOS: 1.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "AudioToolbox",
  "identifier" : "/documentation/AudioToolbox/AUParameter",
  "metadataVersion" : "0.1.0",
  "role" : "Class",
  "symbol" : {
    "kind" : "Class",
    "modules" : [
      "Audio Toolbox"
    ],
    "preciseIdentifier" : "c:objc(cs)AUParameter"
  },
  "title" : "AUParameter"
}
-->

# AUParameter

An object that represents a single audio unit parameter.

```
class AUParameter
```

## Topics

### Querying Parameter Properties

[`minValue`](/documentation/AudioToolbox/AUParameter/minValue)

The parameter’s minimum value.

[`maxValue`](/documentation/AudioToolbox/AUParameter/maxValue)

The parameter’s maximum value.

[`unit`](/documentation/AudioToolbox/AUParameter/unit)

The parameter’s unit of measurement.

[`unitName`](/documentation/AudioToolbox/AUParameter/unitName)

The parameter’s localized unit name.

[`flags`](/documentation/AudioToolbox/AUParameter/flags)

The parameter’s characteristic details.

[`address`](/documentation/AudioToolbox/AUParameter/address)

The parameter’s address.

[`valueStrings`](/documentation/AudioToolbox/AUParameter/valueStrings)

The parameter’s localized value strings.

[`dependentParameters`](/documentation/AudioToolbox/AUParameter/dependentParameters)

Any other parameter’s whose values may change as a side effect of this parameter’s value changing.

### Managing Parameter Values

[`value`](/documentation/AudioToolbox/AUParameter/value)

The parameter’s current value.

[`-  setValue:originator:`](/documentation/AudioToolbox/AUParameter/setValue(_:originator:))

Sets the parameter’s value, avoiding redundant notifications to the originator.

[`-  setValue:originator:atHostTime:`](/documentation/AudioToolbox/AUParameter/setValue(_:originator:atHostTime:))

Sets the parameter’s value, preserving the host time of the gesture that initiated the change.

[`-  setValue:originator:atHostTime:eventType:`](/documentation/AudioToolbox/AUParameter/setValue(_:originator:atHostTime:eventType:))

[`-  stringFromValue:`](/documentation/AudioToolbox/AUParameter/string(fromValue:))

Gets the string representation of a parameter value.

[`-  valueFromString:`](/documentation/AudioToolbox/AUParameter/value(from:))

Converts a string into a parameter value.

## Relationships

### Conforms To

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

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

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

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

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

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

[`NSSecureCoding`](/documentation/Foundation/NSSecureCoding)

[`NSCoding`](/documentation/Foundation/NSCoding)

### Inherits From

[`AUParameterNode`](/documentation/AudioToolbox/AUParameterNode)

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)