---
title: AudioUnitParameterEvent
framework: audiotoolbox
role: symbol
role_heading: Structure
path: audiotoolbox/audiounitparameterevent
---

# AudioUnitParameterEvent

A scheduled change to an audio unit parameter’s value.

## Declaration

```swift
struct AudioUnitParameterEvent
```

## Overview

Overview If the eventType field value is AUParameterEventType.parameterEvent_Immediate, use the immediate structure in the eventValues union. If the event type is AUParameterEventType.parameterEvent_Ramped, use the ramp structure in the eventValues union. Apply one or more AudioUnitParameterEvent events to an audio unit using the AudioUnitScheduleParameters(_:_:_:) function.

## Topics

### Fields

- [scope](audiotoolbox/audiounitparameterevent/scope.md)
- [element](audiotoolbox/audiounitparameterevent/element.md)
- [parameter](audiotoolbox/audiounitparameterevent/parameter.md)
- [eventType](audiotoolbox/audiounitparameterevent/eventtype.md)
- [eventValues](audiotoolbox/audiounitparameterevent/eventvalues.md)

### Initializers

- [init()](audiotoolbox/audiounitparameterevent/init().md)
- [init(scope:element:parameter:eventType:eventValues:)](audiotoolbox/audiounitparameterevent/init(scope:element:parameter:eventtype:eventvalues:).md)

## Relationships

### Conforms To

- [Sendable](swift/sendable.md)

## See Also

### Structures

- [AudioUnitConnection](audiotoolbox/audiounitconnection.md)
- [AudioUnitEvent](audiotoolbox/audiounitevent.md)
- [AudioUnitExternalBuffer](audiotoolbox/audiounitexternalbuffer.md)
- [AudioUnitFrequencyResponseBin](audiotoolbox/audiounitfrequencyresponsebin.md)
- [AudioUnitMeterClipping](audiotoolbox/audiounitmeterclipping.md)
- [AudioUnitMIDIControlMapping](audiotoolbox/audiounitmidicontrolmapping.md)
- [AudioUnitOtherPluginDesc](audiotoolbox/audiounitotherplugindesc.md)
- [AudioUnitParameter](audiotoolbox/audiounitparameter.md)
- [AudioUnitParameterHistoryInfo](audiotoolbox/audiounitparameterhistoryinfo.md)
- [AudioUnitParameterNameInfo](audiotoolbox/audiounitparameternameinfo.md)
- [AudioUnitParameterIDName](audiotoolbox/audiounitparameteridname.md)
- [AudioUnitParameterInfo](audiotoolbox/audiounitparameterinfo.md)
- [AudioUnitParameterOptions](audiotoolbox/audiounitparameteroptions.md)
- [AudioUnitParameterStringFromValue](audiotoolbox/audiounitparameterstringfromvalue.md)
- [AudioUnitParameterValueFromString](audiotoolbox/audiounitparametervaluefromstring.md)