I really wanted atmos but the wife wouldn't let me put any more speakers in the living room. But she was ok if they were hidden in the ceiling!
So I decided to do 4 IB Volt 10s. Only problem is that my living room where the speakers are is on the 1st floor of a 2 story house...no attic so they had to be installed from the 1st floor.
I also didn't want to put a box in the ceiling and make that large of a hole or have a square grill.
I designed a baffle that could fold in half so it could fit in the hole in the ceiling and then when it is screwed into/opened all the way it seals itself.
Here's how I built it for anyone else looking to do the same:
1) Cut holes in the wall the same diameter as the out lip of the baffle.
2) Cut 8, 3/4" mdf boards at 14"x7". I put them in pairs to make 14"x14" baffles and screwed them onto scrap plywood in the area where I would make the cutout for the hole. Next I used the router to make the lip and hole for the speaker. Since the Sheetrock was already 5/8" I only made the lip 1/16" deep so that the speaker had something to catch on but wouldn't go any further up beyond the sheetrock.
3) I flipped over the baffles and clamped them down and then secured the hinges with CA Glue and then screws. Then I added a foam gasket to the seam under the hinges so when it is fully open it creates a nice seal.
4) Then I clamped those down to make the foam thinner and then added hurricane bolts to the back.
5) Next I added a board onto the top to mount the crossover board to.
6) I put a thin gasket around the perimeter of the hole cutout that would seal in between the baffle and sheetrock.
7) Finally I put the baffle in the ceiling and clamped it to the sheetrock and added 4 screws to hold it tight and to create mounting points for my grill covers.
8) I put a 14"x16" piece of insulation in the ceiling that would be right behind the driver. I added each speaker.
9) Made the grill covers. Done!