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# AudioUnitParameterEvent

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

```
struct AudioUnitParameterEvent
```

## Overview

If the `eventType` field value is [`AUParameterEventType.parameterEvent_Immediate`](/documentation/AudioToolbox/AUParameterEventType/parameterEvent_Immediate), use the `immediate` structure in the `eventValues` union. If the event type is [`AUParameterEventType.parameterEvent_Ramped`](/documentation/AudioToolbox/AUParameterEventType/parameterEvent_Ramped), use the `ramp` structure in the `eventValues` union.

Apply one or more [`AudioUnitParameterEvent`](/documentation/AudioToolbox/AudioUnitParameterEvent) events to an audio unit using the [`AudioUnitScheduleParameters(_:_:_:)`](/documentation/AudioToolbox/AudioUnitScheduleParameters(_:_:_:)) function.

## Topics

### Fields

[`scope`](/documentation/AudioToolbox/AudioUnitParameterEvent/scope)

The scope for this parameter event.

[`element`](/documentation/AudioToolbox/AudioUnitParameterEvent/element)

The element for this parameter event.

[`parameter`](/documentation/AudioToolbox/AudioUnitParameterEvent/parameter)

An identifier for this parameter event.

[`eventType`](/documentation/AudioToolbox/AudioUnitParameterEvent/eventType)

The type for this parameter event.

[`eventValues`](/documentation/AudioToolbox/AudioUnitParameterEvent/eventValues)

The values for this parameter event.


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