I plugged the aux in on the back of the unit, a regular stage mic, flipped the Mic button, checked the levels and the back dial, and its was ok, the microphone running on top of any deck. It was, but now its not anymore, and nothing changed between sessions… surely my microphone didn't just break… I see the AUX dial in the lower left under deck A, its greyed, I don't recall was this ever active? There's seems an alternative option for live input qualifying filtering effects on the mic input, I was able to activate this, the whole deck is blank on setting it. Any help?