Sorry for not being more specific. As I mentioned, I have MAIN, AUX 1, and AUX 2 turned on in the Talkback Edit screen (for our particular rehearsal situation, the MAIN is needed, but thanks for the caution). In the MAIN, MIX 1, and MIX 2 Layers, I already had the Talkback fader at unity gain and the Master fader for each at an appropriate level. I have no issues with the other sources being sent through those 3 mixes. I just get nothing from the Talkback channel. The Talk switch itself appears to be working properly since the on/off behavior of the button LED works as expected. I'm stumped.