[glynnw]

Several years ago I built a pair of Danny's dual 10" OB subs which I paired with a succession of Spatial speakers - ending with current X5's.  One of the Rythmik amps developed a buzz so it is off being fixed at the moment.  I control both subs with a DSpeaker anti-mode dual core device.  With just 1 sub I had to rerun the set-up program on the DSpeaker and set it as mono.  At this time I pulled out a mike and took some measurements which might be interesting to some here.  As a mono sub the GR Research starts at 20 HZ and goes easily to over 50 HZ and then tapers off to little output at 90 HZ.  The X-5 subs start in at abt 50 HZ - I didn't measure for an upper limit.  My amps are LTA ZOTL10's run in mono, so the X-5 subs may play lower with another amp.  But overall these subs and speakers are a good combo on this day in my room.  No other guarantees.

[xrqp]

When you say the subs and the X5s are a good combo, is that with 1 sub, or 2 subs, or both?
Does "good combo" mean it sounds better with the subs than without?

I read that the more subs in more locations is better to even out the room response, so it makes sense.

[glynnw]

Sounds better with 1 GR Research sub in mono or 2 in stereo.  The X5 cuts off around 50 HZ and the sub (s) take it down into the 20's.  Even with little music in that frequency, having the subs  just seems to expand the soundstage.  I can mute my subs remotely, so it is easy to compare.