The upside: I don't have to be wondering about a fail point somewhere in the cross over. That center stage being shifted to the left is gone completely. I had my g/f yelling over the music at me. Life is good.
I guess I'll just have to listen to everything again to see what it sounds like wired up right. It took a surprisingly long time to identify that something was off. I level matched everything but just realized I have gain controls on the sub amps that need to be leveled to each other before they get leveled to the mains.
You've had a useful learning experience. You now know how hard it was to hear that something was off. In the MBOW1 2-way, if the mid-woofer and tweeter aren't wired with opposing polarity, there will be a large sound suck-out centered around the 2.6 kHz crossover frequency. See
this graph from Dennis's DIY web site.
It looks huge on the graph but it was hard to notice.
I always remember one guy at a DIY speaker builder's meeting at Dennis's house, years ago. He was proudly demoing his 2-way speakers made with very expensive Seas magnesium 6½" mid-woofer and Seas Millenium tweeter. He bragged about using premium priced made-in-Germany capacitors, expensive flat ribbon inductor coils, and his boutique speaker cables. He claimed that he could easily hear improvements in sound from all of them.
It turns out that he had mistakenly wired his mid-woofer and tweeter with the wrong polarity. He had only finished them late at night several days earlier, as you now know, wiring the drivers to the XO board is one of the last things you do in the final assembly. It's late, you're tired and want to finish up – it's easy to screw up that last step.
Dennis heard the crossover frequency suck-out immediately, but the builder didn't. Dennis, ever polite to other builders, offered to measure them, and showed him the results. It looked similar to the above graph.
I wanted to ask him how he could hear subtle differences (if any) due to boutique cables or high-priced capacitors, but not hear the huge suck-out due to drivers wired in opposing polarity. I never did ask him, but I've always remembered that story as an example of how easy it is to fool yourself.