Musical subwoofer under $2000

I would highly recommend going the two sub route.  You have a decently large space to fill that will surely have peaks and nodes.  With subs 1+1=3!  You have a great system and some good subs will really enhance your listening experience.  Good luck and cheers. 

If you get two subs, you can also try each as L/R mono ( = stereo subs), and you can conversely stack them vertically and run each in stereo (L + R channel signals) to see if an “array” approach improves their “collective” directivity. Stacking may be more difficult with the model (Gallo TR3-D) I recommended vs. the others, but the benefits might (MIGHT) remain the same 😉

Thanks again for all the advice. Right now I'm considering the Rythmik F12 XLR3 gloss white with A370XLR3 amp  or the Arendal 1723 SUBWOOFER 1S in satin white - with the option to go to two later, if needed. I must also admit I'm tempted by the Arendal 1723 SUBWOOFER 2S at $2,500 as a one and done solution.

Like many I was leaning to REL (but only because there is so much hype around them) but from a value for money perspective their prices have leaped enormously in the past 2 years and made them much less attractive from a value perspective.

By the way I saw another thread yesterday on DAC's https://forum.audiogon.com/discussions/dac-recommendations-please-2
and was fascinated by the BARD AI review from @ghdprentice  AI since its trained on existing data is highly susceptible to information bias too, but nonetheless maybe something Audiogon should be looking at and using members feedback?

Highly recommend the Arendal sub.

I use the smaller 1961 1s in my bedroom setup (mostly used for home theater) and found the controls (e.g. variable phase, selection of roll off slopes) very useful and it was surprisingly easy to integrate with the Magnepan LRS+.

@saboros thank you for that input. I'm really torn between the two right now, but I think I like the Arendal better, so this helps.