I use a Velodyne DD15 with my 861v8. I think it is a fantastic sub and way better than the Meridian subs. The new DD12+ has the same output as the DD15 in a smaller enclosure. The onboard room correction is very flexible and works well with MRC.

The DD/DD+ are highly regarded throughout the audio industry.

Phil...

Lyngdorf MP-40, ROON Sever,598DP, Emotiva Gen 3 9 CH amp Musical Fidelity M8500S, Tannoy Definition DC10T and matching centre, Monitor Audio Gold FX surrounds, Velodyne DD15 sub, Sony KD75Z9, Toshiba EP35/Sony UHD X700, Townshend Isolda EDCT interconnects, speaker cable, Musicworks Reflex plus G3 ext block, Q4-ref isolation rack.