Cabinet for in-ceiling speakers

[naylorpd]

We have an apartment in Azerbaijan which is a bare concrete core & shell, so we will fit out everything including a suspended plasterboard ceiling, around 15cm below the concrete that defines the floor/ceiling levels. I'm planning to put ceiling speakers, but have never really used them before, though I am familiar with building (but not designing) speakers in cabinets.

We have two bedrooms and a living room, the idea is to have one pair of Polk RC80i in each of the bedrooms and two pairs in the living room, all powered by 3x WiiM amplifiers (60wpc) which can be linked in-app to provide multi-room capability.

So my question...if I fix a speaker in the ceiling, it if effectively in a cabinet that is around 15cm x 5m x 4m - which doesn't feel like a good size of cabinet for an 8" speaker. Since we are building the ceiling from scratch, it occurred to me that I could make an in-ceiling speaker cabinet behind the speaker using a double-layer of plasterboard, that is a more appropriate size for the speaker. And I'm wondering if this is a good idea, or not?

At the moment I've no idea what size of cabinet it would be (except 15cm deep) or the Thiele Small parameters for the Polk RC80i.

 

[rayma]

Your speakers are tuned for an "infinite baffle" and need no sub-enclosure to work at their best.

Baffle tuning​

With infinite baffle tuning, RCi speakers utilize the “virtual enclosure” of your in-wall and in-ceiling space to enhance their bass response and smooth low frequency blending with the midrange.

 

[naylorpd]

That makes life a lot easier, thanks!