can subwoofers make things worse?

I recently added two Rel T9x, Klipschorns, 13'W x30'Lx9'h room. didn't really add much bass. but expansion in sound staging far surpassed my expectations. I've spent much more on electronics in the past and never experienced this level of expansion, should have done this years ago!

T series Rel's don't reach lowest freq in bass, but I've never experienced this kind  of coherence, integration with other subs, and those with dsp. With other subs constantly fine tuning sub settings with different recordings and volume levels such that it drove me nuts, gave up on subs for years.

I suspect two smaller T series would be seamless integration with your setup, as others have mentioned a single sub more difficult.  Smaller T series won't overload your room with deep bass and should provide very nice expansion of sound stage.

Doubt a sub or two will make things worse, but you have to take the time to find out where they sound best.  I currently am only using one and it’s six feet behind the listening position and only does sounds below 45hz.  You will have to figure where it rolls in and how fast the slope is. Mine is set at 12dbs, I believe and how much volume you want from it etc.

All the best.

I have two SVS micro subs, one sitting beside each of my powered monitors. It sounds well integrated and tight. The room (open floor plan) is 16’ x 24’ with openings all around. 
 

I’m probably a minority here, but I don’t want to see my stereo, at all. If I could buy an invisible stereo I would. So, not that the micros miss anything, but they are as big as I want in the room, and it’s a close call with them. 
 

The phone app is very useful, fyi, and two subs seem much easier to integrate compared to a single sub. SVS has a pretty good shipping and return policy if you are tempted to give it a whirl.  Check out the website. 
 

Hope this helps, best of luck with it!

Yes it sure can if the sub is not time aligned/in phase. I strongly recommend highpassing the speakers (cutting the bass of the mains) through an active crossover as the timing can be corrected. 
 

those small subs don’t play loud and deep. They tend to cut the low bass when pushed hard with digital perfection circuits. Erin’s Audo corner has measurements of a bunch of them on YouTube and probably his website too. Worth watching before you buy. If you have the physical room a good 12” is the way to go was they can always be turned down. 

It's all about what you want.

I believe the REL and the SVS offer easy to return trial periods. One is a sub-bass speaker and the other is a subwoofer. Get both of them at the same time and do your own side by side comparison. It's said they both offer useful phone setup support.

With its dramatic frequency roll off the REL is easily more forgiving of placement at the cost of articulately deeper frequency heft and air. ....Set it and forget it.

If the SVS is properly positioned within your room the flexibility of the remote controlled application adjustments will provide smoother speaker integration, EQ presets and volume control all from your listening position. ....Fun.

All the best with your search.