Redkiwi the sub I used not expensive, but very musical was the nht sw2pi(I own after listing to many subs; rel, paradigm, sunfire, velodyne and a few others) no its not as loud as the above mentioned, but much quicker and not boomy. Hate boomy. Its a 10 inch sub in its on little 16x16x16 encloser with seperate amp/x-over. When I took the speaker wire off the sub on the aerius i I was surprised the to hear the intergration problem. Its easy to try, it you have them biwired just take the wire off the bottom. You do need a seperate sub to fill in the panels. Sedond told me about the cls2 and I think I will be(one day)putting the aerius i to the rear for ht and continueing my hunt for the perfect sub to match those cls2. Funny thing is I would have never believed it until I tried it. Otherwise very difficult to tell. But I still love the Martins!!!! Panels are great and I think one day someone will make a fast enough sub to keep with them. I probably will be several 10 inch subs. I believe but not possitive that the cls2 go down to 40 or 50 hz. Martin is releasing their new sub this fall, hopefully it will be what I'm looking for. pete