Rafael0054, the Apogee hybrid ribbon speakers can sound amazing, if you can find a pair in good condition and if you have the amp(s) to drive them properly. I have owned several models of Apogees over the last 20 years.
All things being equal, I would advise you to select the latest model in the largest size. I would take the Cepheus 6 before the Slant 6, and I would take either before any model Centaur. Being that the Cepheus 8 doesn't exist (for all practical purposes), I would choose the Slant 8 over the Cepheus 6 *IF* I had right room and the right gear.
IMO, your room is on the smallish side for any of these speakers. They need a lot of air around them - 3'-4' from the back (front?) wall and at least 3' from the side walls - more is better. The Cepheus 6 is a little better in small rooms than the Slant series, but not by much. I would try corner bass traps and treating the wall in front of the speakers (behind the listener) if the room proves to be problematic. Or try a digital room correction system like Dirac. Good luck
All things being equal, I would advise you to select the latest model in the largest size. I would take the Cepheus 6 before the Slant 6, and I would take either before any model Centaur. Being that the Cepheus 8 doesn't exist (for all practical purposes), I would choose the Slant 8 over the Cepheus 6 *IF* I had right room and the right gear.
IMO, your room is on the smallish side for any of these speakers. They need a lot of air around them - 3'-4' from the back (front?) wall and at least 3' from the side walls - more is better. The Cepheus 6 is a little better in small rooms than the Slant series, but not by much. I would try corner bass traps and treating the wall in front of the speakers (behind the listener) if the room proves to be problematic. Or try a digital room correction system like Dirac. Good luck