Another thing, running ypao it obviously picks up the rear sub first so it set the distance to 6.8ft but hsu said to set the distance to my front sub. I changed that to 12.6ft\n\nThat’s why you would flip the phase on the rear one. That will add cycles and they should both fire together improving impulse response. I would not gain match them unless they were both up front where they were. Definitely level match them.