<!--
{
  "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/AUAudioUnitV2Bridge",
  "metadataVersion" : "0.1.0",
  "role" : "Class",
  "symbol" : {
    "kind" : "Class",
    "modules" : [
      "Audio Toolbox"
    ],
    "preciseIdentifier" : "c:objc(cs)AUAudioUnitV2Bridge"
  },
  "title" : "AUAudioUnitV2Bridge"
}
-->

# AUAudioUnitV2Bridge

A class that wraps a version 2 audio unit as version 3 audio unit.

```
class AUAudioUnitV2Bridge
```

## Overview

A version 3 audio unit may subclass the [`AUAudioUnitV2Bridge`](/documentation/AudioToolbox/AUAudioUnitV2Bridge) class. If so, the audio unit’s component description should refer to a registered component with a version 2 implementation by using a factory function. The bridge will instantiate the version 2 audio unit via the factory function and communicate with it using version 2 audio unit APIs.

Hosts should not access this class; it will be instantiated if needed when creating an audio unit.

## Relationships

### Inherits From

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

### Conforms To

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

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

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

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

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

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

---

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)