magnapans.7i and subs

I owned Maggie 3.5Rs, I have 2 SVS subs, an Ultra and a Pro. I tried dam near everything to get them to blend, including active XO and BOM- another active device

I gave up, sold the 3.5Rs and now selling the subs if anyone’s interested

I have heard that REL subwoofers are good with maggies, and open baffle subwoofers as well. BTW, you can do a search about magnepan and subwoofers in this forum and see a lot of older posts concerning your topic.

Check the specs before you buy, some subs  don't really go that low. It will depend on the music you listen to I guess.

Hi,
I have a pair of .7's as well and I run a pair of REL t5i's. I also have a pair of Heresy II and a pair of open baffle Caintuck Betsy's with the LII Fast 8 drivers which are super fast! I use them all with the REL's and they too are super fast! Once you work with the cross-over and volume adjusted they really open up. All I did was make a few adjustments and sat back down and listened, then I got back up and made more adjustments. Once I got the feel of it, they blend perfectly with all the speakers. It's like they're are not even there, but you feel it during certain times in the music. I got mine at Upscale Audio. I mostly listen to two channel jazz but sometimes when you hear soundtracks, the impact is felt in your chest. For example my wife downstairs was getting scared because she heard a low sound but didn't know where it was coming from. That's because I was playing sound tracks from Batman Begins and Hans Zimmer. When I play jazz, the bass is super fast, tight and controlled, not mushy or boomy. 

The other thing I really love about the REL's is the way they connect which is unlike anything else. Not only that, but the build quality is really nice too. 

I have listened to the 3.7i's with upscale Rel subs, and it sounded wonderful. Another choice of subs would be Vandersteen Sub 3's. Although they take a bit more ambitious amount of implementation.