... selection for an aggregate device ...
The set up only shows midi inputs from my two devices
An Aggregate Device is a virtual audio device and has nothing to do with MIDI.
If you see MIDI devices in Audio MIDI Setup, you are looking at the wrong window.
- Open Audio MIDI Setup
- Close all windows that are open there.
- In the main menu select "Window -> Show Audio Devices".
- The "Audio Devices" window pops up and you see a list of your audio devices on the left.
- At the bottom left corner click on the tiny plus sign and select "Create Aggregate Device".
- Now you see a new entry in the list called "Aggregate Device". In the right part your audio devices are listed again.
- Decide which device you want to have as master. Normally you take the one you think has a better synchronization. In your case I would take the Focusrite as master.
- Double click on "Aggregate Device" and change the name. For example to "Clarett+UMC". The name should also give you information about the order of the devices later.
- In the right list you see your devices with checkboxes in front of them. First of all activate the checkbox of the Focusrite. This will become the master.
- Afterwards activate the checkbox of the Behringer.
- Now you have the Focusrite in the first line and the Behringer in the second. The numbers are the number of input and output channels. The Behringer should automatically have the "Drift Correction" checkbox checked at the end of the line. That's fine.
- In the upper right part you see a graphical representation of the arrangement of your devices and the input and output channels. This is how you have to set them up in Logic.
The Aggregate Device is ready and from now on you can select it as input and output in any program.
While you use your Aggregate Device, you can't see in the audio applications where the Clarett is and where the Behringer is. You need to know the order and how many channels each device has. If you don't like the order of the devices, you have to change it in the Audio MIDI Setup. The best is to deactivate both and click the new master first and then the other one. Don't forget to change the name of the Aggregate Device, otherwise you won't know your way around later. You can also configure multiple aggregate devices.
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Below is a screenshot as example. I have only one audio interface, so I made an Aggregate Device with my Metric Halo interface and the Mac’s internal speakers:
(This screenshot is from a Mac mini M1 running Ventura, your screen may look slightly different.)
This screen tells me that the Metric Halo is the first one and the master, and is configured for 32 input and output channels. The Mac has only 2 output channels and they are after the Metric Halo. If I want my Logic playback through the Mac’s speakers, I have to select channels 33+34 as outputs.
Your devices have both inputs and outputs and the numbering system applies to inputs and outputs. If you forget the channel numbers and can’t find the channels in Logic, just look at the Audio MIDI Setup, the numbers are always there.
