Is it better to have two matched subs or one

The Velodyne SMS-1 bass manager shows the in-room response of my KEF Reference 1s to be pretty flat to 30 Hz before sharp roll-off, so it's no surprise the location of jazz bass players is well imaged even without the subs.  But the location of jazz bass players is also well imaged by my LS50s.

db

@dbphd I've had the same experience with all the speakers I've had in my room, I didn't mean to imply that the Ref 1s were doing something others couldn't, although they do image better than any other speakers I've owned.

big_greg -- I agree the Ref 1s image splendidly.  I use mine mostly for Roon via ethernet to an Ayre QX-5/20 digital hub with balanced analog to a KX-5/20 preamp and VX-5/20 amp.  For surround and movies I add a DX-5 DSD disc player, Bryston SP3 processor, and 4 LS50s.  A pair of HGS-15s with acoustic room correction extend LF to below 20 Hz.

db

I wish to thank everyone for your help.  My room is 14 x 24.  It is a dedicated room that opens to the house.  The three outside walls are largely glass.  I think I will purchase another sub.  I forgot to mention that I use bucket subs in the back of the room.  All suggestions are welcome.  Thanks again.  Steve