sub sat is bookshelf speakers and a subwoofer,which cinemas use,normally people would use floorstanders for music playback,in your case for movies and gaming sub sat is all you need,the denon should be a good step up in performance,a better sub would also be a upgrade,after lockdown try and go to a store and get a demo.Ah, thanks ever so much for your reply. Sorry, what is a "sub sat" system?,. Also I will be using it mainly for gaming and movies. So do you think I will get a big enough improvement using my same 2000i speakers with the upgraded Denon avr-X3600h receiver? Oh really? So there's no point going from the 2000i set to the 3050i set?