I am not sure I am even hearing the ambience, I suppose I could try unplugging front speakers and listen to what I am actually hearing but I watched harry potter & the P.O.A. and didn't notice any rear ambience, I know you are not supposed to be distracted but since I am going all out to try and perfect the sound as best as I can I was actually listening to hear what was going on and there was nothing. If I turned my head sideways I can suddenly hear the sound but when I stare straight at the screen nadda! Unless it is a flyover sound effect.For exactly what it says the are - surround effects. Mostly, it just adds a sense of envelopment and being IN the movie instead of outside of it. There are some effects that should be heard loud and clear but many are just ambient type of things.