The Default Output Audio Units

Q:  What is the difference between the Default Output and System Output audio units?

A: What is the difference between the Default Output and System Output audio units?

The System Output unit (kAudioUnitSubType_SystemOutput) is for alerts and user interface sound effects. The Default Output unit (kAudioUnitSubType_DefaultOutput) is for all other audio output.

Using the Audio MIDI Setup application (in the Utilities folder), a user can direct the output of each of these audio units separately.

For more information on these Mac OS X audio units, refer to the headers in the Audio Unit framework (AudioUnit.framework).

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