System Configuration : System Setup : Configuring Pro Tools Hardware Settings : Configuring Pro Tools Aggregate I/O

Configuring Pro Tools Aggregate I/O
(Mac Only)
On Mac systems using Core Audio, you can select Pro Tools Aggregate I/O as the Current Engine to use the built-in audio inputs and outputs on your Mac computer. You can configure the Pro Tools Aggregate I/O setting in the Mac Audio Setup, which can be accessed from the Pro Tools Hardware Setup.
To configure Pro Tools Aggregate I/O settings:
1 Choose Setup > Hardware.
2 In the Peripherals list, select Pro Tools Aggregate I/O, or whichever Built-in input or output option is selected as the Current Engine in the Playback Engine.
 
Hardware Setup for Pro Tools Aggregate I/O (Mac only)
3 Click the Launch Setup App button.
4 In the Audio Devices window of the Mac Audio Setup, configure the Pro Tools Aggregate I/O settings.
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The Pro Tools Aggregate I/O device is intended for use only with the built-in audio on your Mac computer. For best performance, use the default settings.