Is this odd? I just haven't seen anything like this. I've seen infinity and Mb crossovers, but there is usually one set of input. If it was to be bi-amp, wouldn't I have to "bridge" the input to get power to both? I see the wiring left from the previous owner and he has one "bridge" on one xover and used a set of + and - on the other crossover. I guess it doesn't matter.