Couldn't agree more with Dave-T. There could be a lot going on with the setup. Yet, I remember seeing an interview in youtube with a Dolby engineer saying that Atmos could be very forgiving as it's very robust.
I was able to finally setup Atmos in a dedicated 'theater' room in my home in January of this year. I bugged the electrician (a pro guy, btw) a lot about the angles and separation in the ceiling because I wanted to follow Dolby's guidelines closely. After re-calibrating the speakers later that evening, looked for a random movie in a premium channel and found 'The Cave' (no particular interest). The crew was already deep in the cave and knew about the creatures. The Marantz was already setup to upmix to Atmos. I don't know how to convey my experience without anyone thinking I'm taking it too far. But wow, the experience was ecstatic. I was amazed at the sound of the water flowing through the walls on the cave and dropping into pools of water like *I was actually there*, there was a sense of fuller immersion in the environment. Overhead sounds were fully integrated with the soundstage, and the creatures making the cringing sounds above were more naturally localized in space.
Let me add, that room is fully closed (is not opened to another space), has a fixed pane window which I have acoustically treated and sealed so that that no light won't come through; and if it helps to some of you, I didn't skimp on the subwoofer..one of the best decisions I've made with this 'hobby' (I ignored it for a while, and I shouldn't have). After some searching, I ended up with an S300i from Power Sound Audio..amazing piece of equipment. I'm mentioning the sub for purposes of the soundstage being created. That although Atmos addition is good, the experience is richer because is not lacking elsewhere.