I haven't heard the 3.6s but I had both the 3.7s and the 2.4SE and the 3.7s are a big jump forwards. It's actually less harsh that the 2.4SEs and incredible control of the low end. It's also less boomy even in a small room.
But put it in a big room with a couple of SS2s and the PX/S1 to integrate them, and you have a superb full range speaker system.
But put it in a big room with a couple of SS2s and the PX/S1 to integrate them, and you have a superb full range speaker system.