How do I put the ambient mics into the headphone mix on the VL3/X?
First of all, you should make sure that you have the latest firmware on your VL3/X (currently 2.0.01 Build 326).
Then you need to take a look in the Mix menu (turn any of the smaller, black knobs) and navigate to the Headphone Mix page with the left arrow button.
If you then scroll right down with the large knob you will find the Roomsense parameter right at the bottom in the bottom left-hand corner. Simply change this selection to a value other than OFF.