Yet another Sub Question

Already half way there, get the second T9x. I have two, easily beats any of the single sub setups I tried over the decades. Far better integration with main speakers, simply an extension rather than an add on. Far more forgiving of sub placement and listening position. Sound stage improved noticeably. I cross mine over at 32hz, 3 notches up from minimum volume level, didn't really need much with my extensively modified Klipschorns. I've also played with various diy cabling and configuration of that wire with my 300B monoblocks, you can do much better than the stock REL cable.

You can make a single sub work if you have freedom of placement. Most probably, you will need long cables running to the subwoofer location that works.

Get two subs!!!

It's like boobs, two is best.

I had recently bought and added a Rel S510 to my system. The upgrade was so noticeable and uplifting, I added a second one a week later and never regretted. Everything works more in coherent and the soundstage is amazing.One is good, two is excellent.