Originally Posted by Rock
I am wondering what would be the performance difference for the Atmos height speaker, the in ceiling M3 and the on-wall M3 mounting on the ceiling.
ATMOS has specs for both top & height speakers.
The actual layout rules are a bit tricky but for the most part Tops point straight down and run overhead. They are recommended over heights. But since many have wiring in place (or perhaps to be compatible with DTS & Auro layouts) they started publishing specs for height layouts as well. Heights are mounted high up over the bed speakers (floor level speakers). I believe they are aimed toward MLP.

terminology wise, I think, this question is about Top surrounds.

Originally Posted by Rock
I am wondering what would be the performance difference for the Atmos height speaker, the in ceiling M3 and the on-wall M3 mounting on the ceiling.
I own both. Short answer… On-wall wins hands down over in-ceiling sound wise … not even close.
The only reason to consider an in-ceiling is esthetics IMO.

Originally Posted by Rock
Axiom told me that you could just take the woofer of the M3 out, then attach it to a stub. The in-ceiling M3 doesn't allow you to aim to the MLP.
1 - I imagine if you’re going to get crazy…. You could mount a in-cabinet M3 (if they make them) in the ceiling …. (Note: I’m not a fan on their in-walls… although I’ve only heard them un-installed … so I may be diss’in them unfairly).

2 - tops point straight down