[David Liao]

Doing this is convenient with the Yamaha AG03MK2 https://usa.yamaha.com/products/proaudio/live_streaming_gaming/ag/ag03mk2/index.html, which lets you send to your computer a stereo mix combining a mic input and stereo line inputs.

You can check your audio interface’s manual to see whether it comes with built-in routing capabilities. For example, a Universal Audio Apollo provides a monitor mix you can use to pull in a mix of audio from your input jacks into FarPlay.

If your audio interface doesn’t have enough inputs for your talkback mic and stereo line inputs for your keyboard (maybe you’d like to connect other instruments as well), you can connect your mic, keyboard, and additional instruments to a smaller mixer that feeds into your audio interface.

You can also combine instrument audio and talkback mic audio through a DAW https://farplay.io/audio-from-another-app/#fromdaw, which is particularly convenient to do on a Mac. Passing your audio through a DAW does add some latency, but Mac audio has very low latency (when you use small buffer sizes in your audio applications), so mixing audio in your DAW might be satisfactory.