Polk in-wall speakers: boxing or not ???

Nico808
Nico808 Posts: 3
Hi everyone,

First of all, let me introduce myself: Nico, 30ish, French living in the US since 07 :cheesygrin:
I've been reading posts for some time now on this forum but posting my first one today.

I wish to installed RC85i (surround, placed 5'5" from floor) and 255c-RT in a near future in my new house. This house is being build right now and walls have not been closed yet :cheesygrin: I just pulled all my 12/4 wires in the living room for a 5.1 installation. Right now, R11 insulation will be added only in the wall where RC85i surround will be installed.

At this stage, I am still not sure if these polk in-wall speakers need back-box or not. I was considering making boxes simply by adding 2x4 studs horizontally for a total volume of 1 cubic feet (with maybe some sealant between all studs). Once drywall cut, I was thinking about placing 0.5" polyfill (or equivalent) on the back and sides of these newly formed "box" and install the speakers.

So, here are my questions:
- do these speakers require boxing ?
- if yes, is this approach the correct one ?
- What would be the drawback with in-wall speakers installed in a 8'x16" (wall height x stud spacing) filled (RC85i surround) or not (255c-RT) with R11 insulation.

Another important parameter: the wall in which the center channel will be installed is common to the master bed room. It is not planed to be insulated, but we could add some R11 for that. Does a back box + R11 would be a good alternative to limit sound propagation in the bedroom ?

All advice would be welcome...as walls might get closed very, very soon :eek:

Thanks, Nico