Accurate and revealing subwoofer

Keep the Dominion no matter what.

Consider adding a JL Audio E series which can master RCA output to the Dominion via a pair of long interconnect cables from Blue Jeans or Monoprice Cables.

After performing a crawl test position each sub near your rooms two loudest bass modes.

Can someone comment on the possible advantages of using DSpeaker or MiniDSP subwoofer equalization over Roon DSP?

Then run the equalized / optimized source signal to the E master sub.

Or, wait for a used Velodyne DD-10 Plus as the master for your Dominion.

Nothing is better than a decent size REL.  They play like woofers rather than thumping bass.

Larry—does decent size mean 10 inch woofer or bigger? I’ve been debating between the T7x / T9x or the considerably more expensive Serie S510 for a small room (13x17)

Used Vandersteen 2Wq with M5HP crossover. A pair would be better.  I have had these for around 15 years, and they do everything you want.  They will never leave my system.

@khashmi 

I think the S510 would be fine in your room. 2 would help eliminate any room modes. Happy listening !