The best speaker for a small room...at any price point.

@jayh31 In my current 12x11x9 space, 

https://systems.audiogon.com/systems/7605

I needed acoustic treatments to make the very small KEF LS50's sound their best. Without the treatments I was getting a headache listening to these small speakers at moderate to low volumes. Now it sounds great without fatigue.
 

The Wilson Beseech Discovery's would be my choice. Super fast and deep bass due to carbon fiber cabinet which nearly eliminates cabinet resonance. 

Kef ls 50 + a sub or two will be hard to better.  

Hi,

I also live in a small appartment, and always had issues with bass boom with ported speakers (Klischp, KEF Q900, KEF LS50), and then I bought ATC SCM 19.

ATC are the no-ported design, and can be kept very close to the wall. Mine are kept 3 inches from the front wall (with some absorption treatment), and there is absolutely no issues with bass at any volume. Obviously other components also play a very important role in tonality and how bass is managed.

Good luck