Subwoofer for Nola Boxer


I recently put a small second system up that consists of a Bryston 2B-LP Pro, Acurus RL11 and Nola Boxers. I would like to add just a tad of bottom end. Any suggestions for a compatible Sub? Something with a small foot print and medium power. Thanks.
rocket94
Thank you for all of your replies. The Boxer is a wonderful speaker that belies its price tag. It has a really engaging soundstage, tight bass and loads of detail. The little Bryston is a really good match. It just lacks that last tad of bass. I generally do not use subs because most of my past speakers, PSB, Dynaudio, and Aerial were 4ohm and I found no need for a sub. 
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Rythmik L12.

https://www.rythmikaudio.com/L12.html

MartinLogan Dynamo 800x.

https://www.martinlogan.com/en/product/dynamo-800x

The Rythmik is servo controlled and is used a lot in music centric systems.

The MartinLogan, although over you budget, will go on sale a few times a year bringing it much closer. Highly rated in music systems, it also has Anthem Room Correction built in to smooth the bass response in your room.
I got a trade in velodyne dd12 fast articulate and very tunable list is 5k

Selling for900

Dave and troy
Audio intellect nj