I recently purchased a second identical sub to improve my theater’s bass response. Here’s what I discovered:
1) The version of Audessy I have in my AVR does not recognize multiple subwoofers, so I was going to have to set levels by hand. Setting levels wasn’t too hard, but trying to find the tradeoff between where the subs sounded best, and where they would be out of the way caused some ‘spiritied discussion’ with my wife.
2) Rob nailed it when he said that even response was more critical than volume. 2 subs improved the size of the sweet spot, and moved where the voids were in the room. I still wasn’t happy with how the bass sounded, as it was only louder, not more accurate. I would imagine that with 4 subs I could really minimize any perception of uneven bass response, but is that the best bang for my buck?
3) I will probably need to address the acoustics of the room if I want to keep improving things. More subs might be a less expensive option than room treatements and a professional analysis of the theater room, but in the long term, I think I would have been better off getting my room analysed and a plan for treatments over buying more subwoofers.