Hi Lenny,
First, I apologize for jumping in so late on this thread. Steve with the Summits in Round Rock here, for reference (aka - scotch and listening parties). Very nice looking system you have. I'm have similar room mode challenges and as I recently added 2 subs, while the extra low end impact is great, the 30Hz room mode peak is not better (maybe worse). I'm also thinking about a PEQ and since the Rives seems to be the only analog high quality unit, it's likely on my short list. I'd love to hear your setup sometime and check out the PEQ on/off to assess the impact. Happy Listening!