Help needed in finalizing Atmos speakers

[headcase]

So I went ahead and purchased one pair of RC60i and received them today. However, when I connected them to my PM5005 for testing (they are not yet installed), I find that they sound very thin and hollow. Is that because there is no cabinet?

How much can I expect the sound to improve when installed in-ceiling? Do I need to get a cabinet made for them before installing in ceiling? Can anyone share some insight on this?

Yes if possible get a compact ported one made so it won't leak out much from around behind.

Once installed u can increase the Atmos spkr ch lvl a bit.