Adding a small subwoofer for music in 2020


I see a few old posts considering small subwoofers, but I wanted to resurrect this topic for 2020.

I have a small office (8x10). I have zu cubes, and a heaven11 billie and small tube amp I like to switch between.
The cubes need a sub but I have limited space. The Billie has a pre out, the small tube amp only has speaker output.

Ideally I would get something that has both high level as well as low level inputs. I haven’t found a lot of truly small units that offer this. So far the only thing jumping out at me is the Velodyne microvee. I like the features of Rythmik, but their 12" units seem too big. JLaudio discontinued their d108.

Anything else in a small sub to round out music I should consider?
m_j_d
REL Habitat.  Occupies no floor space, has both high and RCA level inputs.

Velodyne is long gone and there is no support, service, repairs, etc available.
+1 SVS SB1000.  They offer a long trial period and have great customer service.  Best of luck. 
Serious suggestion?  Get an Anthem integrated and a sub. 

The issue with subs in your space is not the quality of the sub but the effort to integrate them. 

If you want to be done, and done well, quickly, go with the Anthem and your choice of high quality sub.

Best,

E
Small, low cost, EQ and wireless. http://syzygyacoustics.com

https://www.velodyneacoustics.com Still available from a new German owner, unmatched feature set and low distortion.

REL the hydroxychloroquine of subwoofers. Chrome bits, shinny paint and a thirty year old setup procedure.   
After checking with my local hifi shop I picked up a Rel T/5i from them.
I hooked it up using the included high level cable (bare wire to speakon), and following their procedure it integrated very easily and sounds great.

I also heard that some of the Sumiko subwoofers are basically licensed copies of the Rel design, and may be had used for cheaper.