The ProMIX is inserted between the mics and the mixer. Each mic channel on the ProMIX has both phantom power and low frequency cut selectable via DIP switches plus a level control. The balanced XLR line output can be connected to a mic input on the mixer and headphones or a powered monitor can be connected to the Phone/Aux output. And if AC power is not available, the ProMIX runs on batteries as well as with an AC adapter.