Two REL’s S/812’s should be more than enough in your room. I am using a pair of Carbon Limited in my room - 15”D x 30”W. I am with @golfnutz on exploring bass traps before you upgrade your speakers. I worked with GIK Acoustics and they were very helpful. I couldn’t be any happier with the results.
Question for those who use REL subs with Wilson speakers
Question for those of you who have experience using REL subs with Wilson Audio speakers:
I have Wilson Sasha 1s with a pair of S/812s. Love the sound. Before getting the subs, I had considered possibly upgrading in the Wilson line eventually (I had Sophia’s before). However, now I am wondering if it may be more effective in terms of overall sonic improvement to perhaps add a second pair of S/812s or even eventually having 2 stacks of 3 with my Sashas. I am very happy with the sound I have now, so I do not feel like I have to change anything at all; but I am intrigued by this question. Thanks in advance for your opinions.