Here’s how it went, to this point. I just twisted both red/yellow wires together, hooked them both up, and left one off to do the process.The crawl seemed to work in that there did seem to be a couple spots where the bass seemed full, louder. That provide a lot of bass for sure. (I may go back to it, try it again). Then I set them up just outside the main speakers (Mofi 8’s which go down to about 47hz afaik).
I wanted to try the way REL suggests and see if it integrates well that way. Yes, it does sound great- I only use the system for music. I have the crossover at 13 clicks, the vol at 15 and only using one wire. I tried to get good bass but not too much, kind of integrated smoothly. One thing was: I could not tell which PHASE was better, they both just about sounded the same. Not sure how big a deal that is... I may try 2 wires again but I want to be able adjust the volume a few clicks.
And I don’t know if 13 crossover clicks is perfect for the MOFI’s or how far that is- all that I saw suggested was the lower is better.
I do think this has turned these excellent speakers into the best system I’ve ever had, easily. I run an Eversolo A8 and a Musical Fidelity M6si.