Yet another Sub Question

Get a second T/9x.  It does exactly what @ghdprentice says.  Soundstage extends in all directions and imaging improves.   I’m not aware of software for setting up a REL.  Neither of my T/5xes came with software, but they do have good videos on setup and integration.  My pair was relatively easy to get sorted.

what does the REL website speaker pairing suggest? If it says some s/510’s are the answer, then it’s a matter of getting the girl and then save for her twin sister. 👧 👧. 

A single sub can work great for a single listening position, otherwise lots of potential room problems...I bought a single larger REL, then another a year later...single sounded fine, but two was a very nice improvement...

what does the REL website speaker pairing suggest?

9x

Well the REL site does not have my QUAD Z-4.  But the Z-4 are in the same class as say Focal 936 or 948.  I had the 926 prior to the Z-4.    All the Focal Aria series result in a 9x suggestion for my room size.   Thats how I ended up with one. 

I was afraid that REL would not have your speakers. Wish they would up their game and add more. Now I guess the question is, do you plan on upgrading your speakers in the near future. If the answer is yes, then Maybe looking at the 510s would be an option. But still at the end of the day you gonna wanna have two. At least with the 510s you’re on your way to a stack array. Now we’re cooking with gasoline!⛽️