can subwoofers make things worse?

Small rooms are always the source of the a lot of issues, as the bass wavelengths are longer than the room itself.  So is also our visually driven tendency to want to put a sub in a symmetrical location- half way between our mains for example.

So subs will excite some kind of room mode no matter what.    The issue is what do we do to mitigate that.  There are many solutions from bass traps to EQ.  My experience is that using more subs turned down low is better than one big one.  For example I would rather go into a small room with 4 cheap subs placed at different distances along the four walls of the room than one sub in corner.  

I think Duke had the right idea with his swarm product.  Also bass arrays work well, in small rooms or large, Bag End did a lot of work on that.  

So we have more trouble with clients buying one sub that we do with clients buying two.  Almost no problems with people buying 3 or 4.  With ATMOS this is a big issue, as much of the basic ATMOS info says subs in front but that doesn't really work in practice. 

I can only let you know what happened with our purchase of a set of year-old Quad ESL 57s many eons ago. They were sold to us with a Dalquist EQ-1W sub-woofer with a passive crossover at about 80 Mhz. What happened was the mid-range leaked through the sub-woofer, muddying up that glorious renown mid-range of the Quads. We did not try an active crossover or bi amp the system, which would maybe have made an improvement. My suggestion: just don't.

Kef Kc62 Is good I use that little guy in my kitchen system.

Rel is not good until S models or Carbon special

SVS is for home theater

i use JL Fathom F212’s in my big system. 
look at the JL E Sub

Remember using one Sub can make it worse easier!

it’s easier to integrate a pair of subs properly and balance out the room better

Thank you all for the replies. 

To answer some questions asked of me. It would be used for both, but primarily music - to add the bottom octave my speakers don't reach (48hz - 23khz). 

 The speakers are 2 feet from walls, and 6 feet apart and i sit 5 feet from them, dead center. The speakers "disappear" and fill the whole space in front of me. 

I live in a rented studio apt with no one underneath me. No issue with adjacent neighbors - only the guy who lives above me. He's been pretty cool so far. I wouldn't play the sub loud - just subtle addition of that low bass. 

I barely have room for a tiny single sub. A pair is not possible. 

Ive read recommendations for all 3, but the SVS micro may be the best combination of size, cost, and being able to set it from my listening position. 

Of course - last night i listened to James Taylor and Billy Joel and didnt feel like i needed a sub. Sounded great to me. But the common thought is, as soon as i add a sub ill hear what i was missing. I was told Best Buy Magnolia has SVS and KEF subwoofers. I can try to see them there.