It seems the hiddeness is big on their list.

But how is coverage and quality of the sound addressed by the speaker manufacturers and by buyers? Reading the other posts here on in-ceiling speakers, they seem to have a poor reputation yet of repeated interest by buyers.

What I mean is, I'd think the sound is mainly on-axis directly below it and spread (diffused and reflected) or absorbed by the flooring material that's also directly below it. Perhaps the manufacturer attempts to compensate for these issues (via sales picth or design).

Also, I see various sizes in diameter. Are these intended to help the quality? If so, what's the typical/recommended minimum for a typical HT/audio set up? How do people avoid "blasting" the listener seated below/slightly off-axis?

Thanks!