Dolby Atmos is based on quite a different way of mixing sound for movies. Instead of a filmaker deciding which speakers to send the sound to (as in 5.1 or 7.1) a filmmaker just decides where they want the sound to come from in the room. A processor then decides (based on how your room is set up) where the sound should be produced. This should leave us with much more interesting and believable soundtracks to films
This technology has already been used in many new film productions and can be heard in some of the best cinemas in the world.
The second new aspect of Atmos is adding arrays of speakers above the listener. This gives an extremely immersive sound and can really transport you inside a scene.