Please Note Loop-back is only available on the iD44 MKII, Loopback is not available on iD44 MKI as the hardware does not support it.
The iD44’s Mixer Application includes the ability to loop-back audio so you can record or stream audio from different applications on your computer using the dedicated Loop-back channels.
These loop-back channels are input channels 21+22 and using the “Input Routing” option of the “Setup” menu of the iD mixer, you can select the audio source to be sent to these loop-back channels.
macOS:
Windows:
The various sources you can select from in the menu are as follows:
DAW 1+2 - Any audio being sent to outputs 1+2 of the iD44
DAW 3+4 - Any audio being sent to outputs 3+4 of the iD44
DAW 5+6 - Any audio being sent to outputs 5+6 of the iD44
DAW 7+8 - Any audio being sent to outputs 7+8 of the iD44
DAW 9+10 - Any audio being sent to outputs 9+10 of the iD44
Master Mix - The audio mix created in the EVO mixer on the Main Mix panel
Cue A - The audio mix created in the iD mixer on the CUE A panel
Cue B - The audio mix created in the iD mixer on the CUE B panel
Cue C - The audio mix created in the iD mixer on the CUE C panel
Cue D - The audio mix created in the iD mixer on the CUE D panel
Using the Loop-back Mix
To record or stream your loop-back mix in your audio software, you would simply need to select the Loop-back channels as your input channels in your audio software. Depending on the software you are using, they may appear as either Loopback 1+2 or Input 21-22. For example, the image below shows how you would select the loop-back input in Logic Pro X.
A similar process would be used in other software. If you are unsure about how to adjust the input on your Audio software, we’d recommend referencing the user manual for your software. On Windows, you may also need to adjust the audio device in your System settings from Analogue 1+2 to Loop-back 1+2.
Please note: Some software will not allow you to adjust the input channel you are using and will just default to Channels 1+2. This limitation with some software can stop you from using loop-back with this software as you are unable to select Channels 21+22.
Recording/Streaming your Loop-back source
Once you have selected the Loop-back Inputs as your audio source in your recording/streaming software, you can now set up your Loop-back mix using the iD Mixer.
The first step is to decide which source you will use for your Loop-back stream.
If you wish to combine audio from your computer and microphones/instruments into a single mix then selecting either the Main Mix or one of the Cue Mixes is the best option as you can use the faders in the mixer to send multiple channels to the same Mix.
For example, below you can see the CUE A mix being used as the Loop-back source with the Mic 1 and DAW 1+2 being sent to the CUE A mix. When recording the Loop-back inputs with this setup, you would hear both the Mic Channel and the Computer Playback on a single stereo channel.
Otherwise, if you only wish to send audio from the computer without any microphone signal, you can just use one of the DAW Channels.
When selecting a Channel or Mix as the loop-back Source, a small loop-back icon will appear on that channel/mix so you can check where the loopback is being fed from with just a quick glance. 
Adjusting your Output Channels
When setting up your Loop-back mix, you may wish to set up your computer audio so it is sent to DAW 3+4, DAW 5+6, DAW 7+8 or DAW 9+10 in order to keep it separate from your Main Monitor Mix which typically will be sent to DAW 1+2.
In most DAW software, you should be able to create a new output send or adjust the output channel. The process to do this will vary so we recommend that you reference the user manual for your chosen software o how to adjust the output channel.
On Applications that don’t give the option to adjust the output channels (Media Players, Video calls…etc) then you may need to adjust this in the System Settings.
macOS:
Open Finder and navigate to Applications > Utilities > Audio MIDI Setup. In the Audio MIDI Setup Utility, select the iD44 MKII from the list of devices. Select the Output tab and then click “Configure Speakers”. You can then select which channels on the iD44 you wish to be your left and right outputs. Channels 3+4 will relate to DAW 3+4, Channels 5+6 will relate to DAW 5+6...etc
Windows:
Open the Start menu and select Settings. In the Settings navigate to System > Sound. Using the “Output Device” drop-down menu, you can select the channels you wish to use for your Output. Again, channels 3+4 will relate to DAW 3+4, Channels 5+6 will relate to DAW 5+6...etc