I have the DSP Pro MK2, and I suspected that I had possibly wired a couple of the inputs backward. I don't know about anyone else, but when I first got the Helix I had a hell of a time getting the inputs to stay connected in the plugs, so I did something unconventional to make them kind of permanent. So I put on some pink noise and broke out the multi-meter. I disconnected the input plugs from the Helix and went through each input by putting the probes from the MM through the openings on the the input plugs to check for negative readings. I found that two were showing negative. Since I had made those connections somewhat permanent, I inverted the polarity on the inputs screen. I re-ran a bunch of measurements in REW and all looks pretty decent, a bit of improvement. The system also sounds better. I thought it sounded pretty good before, but now it sounds more clear and has improved separation. My question is this: Am I fine leaving it this way, with the polarity "fixed" via the DSP setting? I'm uncertain if that is the same as a physical re-wire, or if via the DSP is just applying some all-pass filter like when you mess with the phase slider on each output driver.