A:Answer I tested them with Pirates of the Caribbean At Worlds End, and the rear speaker were barely audible. (2007)
I then tested the system with Pirate of the Caribbean Dead Men Tell No Tales (2017), which has scenes with Dolby Atmos, and the rear speakers sounded great.
Haven't had the chance to do other testing to see if its because of Atmos or because of the age of the films.
But they are capable of good sound, its just what you are playing.