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# Audio Unit Output Subtypes

## Topics

### Constants

[`var kAudioUnitSubType_DefaultOutput: UInt32`](/documentation/AudioToolbox/kAudioUnitSubType_DefaultOutput)

[`var kAudioUnitSubType_HALOutput: UInt32`](/documentation/AudioToolbox/kAudioUnitSubType_HALOutput)

[`var kAudioUnitSubType_SystemOutput: UInt32`](/documentation/AudioToolbox/kAudioUnitSubType_SystemOutput)


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