There is a “hidden” (and easy) way to create an output device of both your mic and your system sound. It is detailed in this article but my short version is here:
- Open Finder
- Launch “Audio MIDI Setup”
- Click the + button to add a device, “Create Aggregate Device”
- Check the boxes for “Use” next to Built-in Input and Built-in Output (or whatever devices you want)
- You can rename the device by double-clicking the name on the left hand list
- In Discord (or wherever) Select the aggregate device as the input.
Bonus Pro tip: To prevent alerts passing through to the channel, Option+Click the little icon in the very top left of your screen. That will gray it out. Thus incoming iMessages will no longer pop up or ding.