An Aggregate Device in macOS allows users to combine multiple audio interfaces into a single virtual device. This can be particularly useful for audio professionals who need to use multiple microphones, speakers, or other audio inputs and outputs simultaneously. By creating an Aggregate Device, you can route audio from various sources into one cohesive system, enhancing your audio setup's flexibility and capability.

Creating an Aggregate Device is a straightforward process using the built-in Audio MIDI Setup utility in macOS. This article will guide you through the steps to create and manage an Aggregate Device, ensuring you can leverage multiple audio interfaces seamlessly.

Examples:

1. Opening Audio MIDI Setup:

   • Open the Finder and navigate to Applications > Utilities.
   • Double-click on "Audio MIDI Setup" to launch the application.

2. Creating an Aggregate Device:

   • In the Audio MIDI Setup window, click on the "+" button at the bottom left corner and select "Create Aggregate Device."
   • A new Aggregate Device will appear in the list on the left. You can rename it by double-clicking on the name.

3. Configuring the Aggregate Device:

   • With the Aggregate Device selected, check the boxes next to the audio devices you want to include in the aggregate.
   • Ensure that the sample rates of all selected devices match to avoid synchronization issues.
   • You can also adjust the clock source to ensure all devices are in sync. Typically, you would set the clock source to the device with the most stable clock.

4. Using the Aggregate Device:

   • Once configured, the Aggregate Device will appear as an available audio input/output in your audio applications.
   • Select the Aggregate Device in your audio application's preferences or settings to start using it.

Script for Automating Aggregate Device Creation (Optional): While creating an Aggregate Device is primarily a GUI-based task, you can use AppleScript to automate some parts of the process. Here’s a simple script to open Audio MIDI Setup:

tell application "Audio MIDI Setup"
    activate
end tell

Save the script with a .scpt extension and run it using the Script Editor or from the command line using osascript.