Behringer X32 Quick Start Manual page 21

Using the Talkback Section
1. The X32 has the option of using the built in talkback mic or external mic.
2. To begin, press view near the Talkback Section on the console.
3. Press the 2nd rotary encoder to switch between internal and external mic.
4. Use the 4th rotary encoder to route the talkback to the appropriate mix busses.