I think this matters only if you have a lot Auro 3D titles you are going to listen to. In my experience, I do have several Auro 3D discs that I used to play when I first received them, but not at all anymore. There is so much more Dolby ATMOS content coming out now that I personally wouldn’t even worry about Auro 3D speaker setup.
When I tested my overhead speaker locations, I tried several positions. When the speakers were placed in the front height positions along the front wall above the mains, the sound obviously came from the front above the speakers. There was only a few degrees of vertical separation. When I moved those speakers to the center of the ceiling between me and the fronts, the sound now came from ABOVE me. It made a huge difference and is much closer to the Dolby ATMOS setup specs. I believe you should follow the overhead speaker placement design specs as closely as is practical to get the intended 3D effects from ATMOS.
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My first speaker configurations were compatible with Auro 3D, ATMOS, etc. You had to choose the correct speaker configuration in the Marantz setup that enabled this compatibility. However, the true speaker positions weren’t matched with this configuration. Later, I moved my Front Height speakers to a (center) Top Front and Top Rear positions, but left the amp configuration set for Auro 3D compatibility. I used this configuration for a long time but it always bothered me that the physical placement didn’t match the amp’s configuration. I also found that I wasn’t playing the Auro 3D discs anymore. I finally went back in to the amp’s setup and changed it to the Top Front, Top Rear configuration and I immediately noticed an improvement with ATMOS play back. The sound field changed and became more focused.
Anyway, I just thought I’d share my overhead speaker placement experience with you.