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.

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. So on-wall M3 may work just as good as the in-ceiling one.

Thoughts?