If you select any of the few THX certified in-walls/ceilings - they are sometimes adjustable to their placement/or recommend placement if not - to keep THX standards - one of the 7 THX rules for sound quality is the speakers ability at imaging correctly with the other speakers placed by this standard. Therefore THX demands that these speakers point source the image at precise positions in your space, so, these speakers can be depended upon to deliver the caliber of sound quality you are looking for. All other inwall/inceilings regardless of brand will be a shot in the dark.
Good luck/have fun/enjoy
Good luck/have fun/enjoy