An aggregate audio device allows you to combine multiple interfaces and access them as one unit. So, for example, if you have one interface with 2 inputs and 2 outputs and another with 4 inputs and 2 outputs, you can set them up as an aggregate device so that your computer will recognise them as one interface with 6 inputs and 4 outputs! Lovely stuff!
Please note that this information details how to set up an aggregate device on a Mac with the 10.5.8 operating system and although the principles are likely to remain the same with future OSX updates, some of the screenshots may not exactly match what you see on more up-to-date operating systems.
To set up an aggregate device on the Mac OS:
1. Ensure that all devices that you want to combine into an Aggregate Device are connected to your computer.
2. Within your Mac Finder, navigate to Applications → Utilities.
3. Find the Application called ‘Audio MIDI Setup’ and double-click to open it.
4. Select Audio → Open Aggregate Device Editor from the Audio MIDI Setup menu bar (or use the Shift-Command-A keyboard shortcut). This should open up the Aggregate Device Editor window.
5. Press the '+' button to create a new Aggregate Device.
6. Click the Aggregate Device name within the upper pane of the window to rename it.
7. Within the lower pane, select the ‘Use’ checkbox next to the names of the devices that you want to combine in your Aggregate Device. Remember – the built-in input and output show up as 2 separate devices.
8. Select ‘Done’.
Your aggregate device is now set-up and should be available for selection within your preferred audio program(s).
Click Here to learn how to select your aggregate device within Logic Pro.