I had a pretty productive day today. Before I get into that I realize I didn't share much about the design of the room. I'm still trying to dig up the plan that I drafted but do have a couple of sketchup shots I can show. Without a doubt the largest influence on the design is the Cinemar build. I have been fascinated with the incredible design and amazing attention to detail that when I sat down to design mine, whether I knowingly implemented a number of the same approaches or not, they are there as you can see.
The room is turning out to be a lot smaller than I had anticipated. It is 20 long by 16 wide. There will be 18" behind the screen leaving roughly 18' from screen to back wall. I am planning for a 150" 2.35 screen with a seating distance of 15'. The room is wired for 11.8.4 but I will be starting with a modest 7.2 setup. ATMOS will follow shortly after I'm sure, just having to make a few compromises due to some budget overruns in the build process.
Today was HVAC day. The room is fairly tight at this point. Although the door is still a simple hollow core and the drywall is not up yet, the air is very stale making work difficult. Because of the location of my main heat trunk running the entire length of one side of the room and the cold air return taking up 1/3 of the other side of the room, circulation will be a challenge. The plan has been to install a single 6" heat source through the soffit in front of the screen should heat be needed. Because the room is in the basement I'm sure I will be able to normalize the temperature through circulating fans. There is space on the opposite side of the screen wall for a single, large dead vent housing both a supply and return fan.
Because of the congested soffits I didn't think there would be a way to run the return to the back of the room leaving only the supply at the front as is widely suggested. Also, with the heat supply in the front soffit there would not be room, nor would it make sense to put the circulating feed and return in the front soffit as well. So, the plan has been to keep the heat source in the front soffit and run the circulation supply and return in opposite sides of the stage. Far from ideal I know but I felt that was the only option. During one of my regular 2:00 am awakenings I had an idea. There is room under the cold air return to fit 2 4" ducts. Bingo. The plan now is to run the 2 4" ducts down the soffit with the cold air return to the rear of the room as the circulating return and run a 6" duct to the front soffit for the circulating supply. So the front soffit will have the heat supply on one side and the circulating supply on the other. The rear soffit will have the circulating return on one side and most likely a vent pulling air from the projector shelf that will be build into the soffit, on the other side.
Off to the races, but wait a minute. The side soffits are not part of the sound proof envelope due to the duct work. If I am punching 2 4" holes in the soffit to run the circulating return lines I am creating an opening for sound to escape. The best approach would be to build a dead vent in the soffit to run the duct work but there is no way I was going to rip down the soffit. Far to much sweat and tears when into ensuring the soffit was true. Okay then, I had to bite the bullet and attempt to build a DD/GG dead vent inside an existing 15" tall by 18" wide soffit. If anyone is wondering how long that takes, the answer is 6 hours. Man was this difficult. My arms look like I've been rolling in cactuses and every joint in my body aches but it's done. I had originally planned to run the dead vent the full length of the soffit but there would be no way to jimmy the material through the small openings. Warning: it's not pretty but it will work.
With that behind me it was on to the dead vent. Before I could close the area in I had to tie in the cold air return that feeds the main room above the theatre. For this a ran an 8" insulated duct from the tin run in the side soffit to the main return trunk.
Duct coming from the tin run out of the theatre.
I installed an 8" extension into the side of the main return truck to connect the flex duct to.
Then simply connected the duct
Sure is nice to know that return is connected once again, it's been two years since I torn the original duct work down. Next it was onto the framing of the dead vent. This went very well and I was complete to the this point within a couple of hours. I followed Ted's guideline as best I could. Everything went to plan except one small error; I failed to account for the DD on one of the sides. Not a big deal, I simply installed the DD inside the frame vs. outside. It shouldn't be a problem as none of the vents framing is in contact with the house framing.
That's it for today. Tomorrow I hope to run the circulation supply and return into the dead vent and close off the top. Till then.