Subs and the quest for bass.


I recently picked up a Rythmik Audio F12SE subwoofer to compliment my B&W 805S. Happy with it, and the Rythmik has very musical bass. I am using an active crossover (NHT-X2 crossing at 80hz) and a Velodyne SMS-1 sub equalizer to even out the low end response. (I have a lot of bass modes.) The SMS-1 is very useful, and with help of quite a bit of EQ, my low end response is almost perfectly flat.

While it sounds great, I keep wondering how different the sound would be if I didn't have to use so much EQ. Then I started thinking maybe I should add another sub? When I started I told myself I would not do it. Also I had so much trouble getting good placement and setup with the first sub, I don't know if I even want to further complicate things.
nemesis1218
I see that I dropped one sentence re: my specific set-up.
I always sit in 1 spot - no variation. If you move around in your listening room, the second sub will definitely provide benfits vis a vis an EQ'd single sub.

Marty
I added a second subwoofer (B&W) and it does make a noticeable difference in room loading. While the first sub probably provides enough LFEs, there was an obvious dead area in the far corner of my large room. The second sub simply fills that void and provides far more balance in the low frequencies. Not absolutely necessary but simply a strong preference.
If I get the second sub, I'm guessing the best possible placement would be to pair one with each speaker, correct? Another benefit of that is I could also cross over higher. Right now my room is set up so the speakers are in the exact middle of the room. Should I place one sub on each side wall, lined up with it's respective speaker?

Also right now my speakers are in a dedicated room and have nothing to the right or left of them. Would placing subs near them affect the sound of the speakers any, or cause any negative impact in imaging? The bottom of each speaker (using b&w 805s bookshelfs on stands) is 7 inches taller than the subs.
Sorry for the triple post, but one last thing, if I were to use the above mentioned placement, how would I set the phaseof each sub? Would it be the same on each of them? (0 I'm guessing?)