Add a second sub or...

It would be easier to give advice if we knew more about your system. Best of Luck

I believe you're asking for your stereo system but, I'm going to respond in HT. I just placed a third sub in my HT. I had one in LFE, one (speaker line connected) as part of the center ch (making it full range), and NOW one connected through a Speakon cable to the front R/L speakers. It reduced the BOOM effect but smoothed out the blend. I have more natural, impressive bass. The surround is better defined with voices more detailed. I use a single sub in my stereo setup. I would use two if I had them. I expect you to benefit significantly from a second sub.

Needfreestuff -
Essence Reference Super Gems, Essence Jasper II monoblocks, Musical Design Chameleon Elite Ultra pre, VPI Classic 3, Arcam FMJ 23 cd, and all Intuitive Design wire..Design of monos necessitates wiring Rel Storm III to the left speaker in lieu of terminals of a monoblock. If I were to add a second Rel, it will be wired to the right speaker.