Best subwoofer below 40Hz for Magnepan .7?

I had some .7's and had the same issue you are talking about. I had one 10" Klipsch sub from the early 2000's and bought a matching sub for it on ebay for $140. I put them in opposite corners of the room and they filled in perfectly. They wanted a really low crossover too, I had them at a little under 80 Hz. I also had an Outlaw Bass Controller (ICBM) to pull some of the low bass of the .7's. I think that helps too.

FWIW, still ended up getting rid of the Maggies, they just couldn't hit hard for the music I liked  (Rock and Roll).

I agree on the Vandersteen 2Wqs.  I have had a pair for a number of years and they are excellent, and a good match for any speaker that reaches down to 40Hz.  Easy to place, easy to dial in and because they take the signal from your amp's speaker jacks, they will mate well with your main speakers.  I would recommend eventually upgrading to the outboard M5-HPs crossovers, as I did notince more transparency with them as opposed to the basic and less costly in-line filters.

The Schiit Loki is an interesting alternative. Unfortunately, having measured a few different subs in a few different rooms, it's going to be a little limited. I mean, it's worth the $150, but often in a sub there are 2-3 narrow bands which need to get cut by a great deal between 20 and 80 Hz.

Add to that I like to use a descending FR, from 20 Hz, loosing 1-2 dB / octave. (JL does the same).

Also, I have never heard a downside in using a miniDSP or similar in a sub only situation.

Still, the Loki may be worth having for other reasons. It is certainly cheaper and more effective than swapping cables to dial in the right sound. :)

Best,

E

I understand how "digital nannies" work, I've experienced them firsthand (a friend who produces some of the concerts I mix is an early adopter of an Antimode), and will assume the esteemed willemj and additionally steamy mister Squires have not tried a Loki, and why would they? It doesn't necessarily replace the Aunty Mame nanny, but it works as I described it, and allows the user to infinitely tweak things to their hearts desire over various frequency bands allowing one to simply become Knob Turner. Sometimes simple is better…much better. My issue with digital nannies is that there is an  extremely wide range of choices made by engineers in mixing recordings, and over decades of not only testing home audio bass response AND live concert bass reinforcement (using state of the art testing systems), my ego refuses to let nannie designers call my shots, so to speak. Plus, I don't have room in my gear rack for a DSP…that might be the main reason right there.

Now that I've researched the Antimode 8033 I might have to get one someday as it's small enough to fit in my rack…note that my aforementioned ego won't allow me to retract my seemingly endless arguments against these things, so I won't say anything if it works. That's just how it is.