How To Add A Sub To B&W N802's

I use a B&W ASW 850 sub with the Velodyne SMS-1 sub controller. I have B&W 800's with this setup and run them full range. I cross the sub at 40hz and have experimented with al the options on the sub EQ to arrive to where I am at right now. The bass at the sitting position is just right and not boomy. It will take some time to dial in a sub. I have used several subs and to me it seems that you can get almost any sub over 12" to blend fairly easy, especially the sealed design subs. I chose the B&W ASW 85o sub for it's deep bass response, 14hz and it fits well into my listening space.
Ciao,
Audioquest4life

I been looking around and it seems a used AWS850 will be much cheaper and do about the same as the 855

sorry ASW850 not AWS (typo)