Subwoofer for Wilson Maxx2


my room is about 22x33 ft, my maxx2 are sitting about 11ft from the front wall, and 8,5 ft apart

i get very good image, width..depth..etc.., however not enough bass

i tried to locate the maxx closer to the front wall, from 4 ft..etc.., however at 11ft everything are better, but not enough bass

so i want to add 2 subwoofer ...wondering any Maxx2 users or full range speakers user are running subwoofer and able to give me some suggestion ?

i do not want to spend that much for Wilson Sub...
mgmmgm
Sorry, I was on family vacation. I have used Tara Omega, and currently use Transparent Opus. Both are excellent, however the transparent are unparalleled in my (limited) experience. I have demoed a few others (Valhalla, Kubala) which had definite weaknesses. I would try the best transparent you can afford. I'm sure there are others who may have cheaper recommendations. Despite what has been written since my last post, I stick with the JL113 recommendation. The Alexandrias have even more woofers than the Maxx and they still benefit greatly from the subs (which have smaller woofers). Plus you can place then wherever you like to reinforce them, and they have room correction.
those opus...is...so expensive, this why i wonder.if i go for second tier Transparent..what may be a good altenative

thx