Best subwoofer below 40Hz for Magnepan .7?

My Schiit Loki is usually in its bypass mode, but if a recording lacks treble energy (or "Fletcher Munson Curve" based late night low volume tweaking is necessary) the highest frequency (8kHz) adjuster will bring sparkle in, and really get the cymbals highlighted smoothly, and the same with the reduction or addition of bass. I rarely use the midrange bands. It might be the best 150 bucks I’ve spent on any hifi gadget as it’s really useful and I haven’t had tone controls on a preamp for a long time. My current trepidation regarding an Antimode box regards my hesitation of adding another thing in the line to the amp, and the fact that I don’t seem to need it in my listening room. But if I find one cheap enough I may still give it a shot for fun.

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.

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.

Unclemode? For 150 bucks I highly recommend a Shiit Loki EQ, as long as you don’t need a balanced thing…or you can loop it…in any case, unlike a digital EQ that’s on all the time making decisions for you (unless it’s off), this thing has 4 bands to be used whenever you feel like it, and the lowest pot, centered at 20 hz, is a very useful lumpiness extractor...you get 4 knobs to play with so it’s also a useful cymbal enhancer and mid weirdness adjuster. Also can be used as a paperweight, a really bad flashlight, and if you remove the top that can be used as a mediocre ashtray. It’s extremely quiet with zero switching noise or bothersome snoring. I use mine sparingly but hey…it’s a cool gizmo. Schiit should pay me for this plug but do they? NO…damn...

Used RELs…I have 2 that cost 200 bucks each, and they're great…a Q150e (10"), and a Q108II (8"). Killer, go well below 40 hz (note that the fundamental tone of a low E note on a string bass is 41hz, although higher harmonics are also there for your enjoyment).