SoapySmith's Theater Construction Thread

After lurking a long time on this site (and after occasionally posting on the rare occasion where I thought I might have something worthwhile to add) and after learning all kinds of great information by following the awesome construction threads in this area, it looks like it's about time for me to start my own.

A little background on my space. My wife and I built our house last spring/summer and moved in just over a year ago. We worked with a friend who is a custom builder and let us basically design the house ourselves. The theater, before drywall, is 23'10" x 17'3" x 8' ceilings and has a 12x12, 14" deep pit in the floor for seating instead of building a riser. I am planning on doing insulation/doubledrywall/GG construction... No RSIC clips because my trusses are 24" on center and it sounds like the gains from using RSIC on the ceiling in this situation are marginal, especially when one factors in the cost.

Currently I am at the insulation/electrical/HVAC stage. I can't completely isolate the HVAC, but what I am planning is to have my heat enter the room through flexiduct in a soffit, go through a smarthome thermostat-controlled damper, and then through duct-board constructed ductwork, which I understand acts as a muffler for sound (per Sandman's thread). Return will be at floor level on the other side of the room. Additionally, I'm thinking of installing at least one, maybe two completely independent lines with thermostat-controlled fans which will suck heat out of the room (soffit level) and send it into other basement rooms if and when the room starts getting warm from people and equipment. Of course, to avoid creating a vaccuum with this, I'll also provide a flexi-duct airway into the room from an adjoining room (floor level). This all makes sense in my head but if it's completely half-baked, someone please tell me now!

My biggest question, and my main reason for starting this thread now rather than waiting until I've finished more of the room, regards the placement of the doors to the room. The room features a main entrance (on the right in the picture below) and an equipment room (door on the left in the picture below). Both of these doors are close to the back corners of the room, where I should be installing bass trapping (although I can do trapping in the front corners and upper rear soffit corners).

I can move the equipment room door 4-5 feet in, essentially flipping the side of the equipment room that the door is on. Also, the main door to the room, as framed, is 48", giving me 14" or so to move that door off the corner and further towards the front of the room. The problem with both of these options is that moving the equipment room door forces me to put my rear speakers in the corners, which, with my room dimensions, is a pretty wide placement. Similarly, moving the entrance door towards the front of the room will force me to have my side surrounds (polk R15's) further forward than I would like (probably well in front of the second row of seating - if I leave the door towards the rear corner, I will frame in the front 14" of the door to give me more wall there). Here is the picture:



So the question for the experts is: Do I let bass-trapping take priority over speaker placement -- considering I can bass trap in both front corners and in the rear corner soffits -- or do I keep the doors towards the corners on the assumption that the front and soffit trapping I have will be sufficient?

(FWIW, here's a picture of the front of the room as well):



Thanks in advance for everyone's help and support. If this thread results in one good idea or learning moment for one forum member, I'll figure it was a success. Hopefully it, like all the other construction threads have done for me, will have lots of these "successes!"

Thanks for the replies, guys -- Eddie, I was sorry to hear about your injury -- hope you are able to get back in the swing of things soon!

Okay, an update -- finally! I left the doors where they were and am almost done drywalling the room. (Will post pics soon). I did double drywall with 66% coverage green glue, Also I have R19 in the ceiling and walls (2x6 wall construction as the walls are load-bearing). Should give me pretty good results, although I won't know for sure until I get some doors on the room.

Which brings me to my question: I am planning to use the masonite safe n sound doors in an exterior jamb with weatherstripping, etc. I understand that this only provides an STC of around 30 and ends up being the "weak link" in comparison to the greenglue/doubledrywall. I also know that communicating doors are usually the best option for soundproofing, but most of the places I've heard them discussed, they're used somewhat separated from each other.

My question is whether I can put two safensound doors on the same jamb right next to each other, in the same way you would mount a storm door and an exterior door? i.e, one opening in and one opening out? Would this improve my isolation much? Or will this just create a resonant chamber and do more harm acoustically than it benefits me isolation-wise?

Time for some pics!

Here is a shot pre-drywall, with insulation in:



Here are a couple of the room with drywall done (2 layers w/ GG), soffit framed, ceiling drywall finished and sanded, screen wall partly framed, and electrical started.

Front:



Back:



The open area in the rear soffit is where my PJ will go; once the GOM and trim are on the bottom of the soffit it will be concealed within the soffit itself.

Next steps are to finish the screenwall framing and finish framing in the floor and step into the seating pit. I ordered some coaster director chairs on the last powerbuy; I was going to go with berklines but in the end decided to go with the coasters because i really like the look of the directors for what I'm going for in this theater.

I decided to order those seats far ahead of when I needed them not only for the powerbuy, but also because I wanted to make sure they'd fit and look the way I wanted them to in the pit before I finalized the design/framing of that area. REALLY glad I made that choice as I definitely changed the design from what I originally had in my head based on seeing the seats in there.

Once the framing is done I'll be finishing off the HVAC, wiring, and painting the ceiling (black). Then it's on to carpet before I do any GOM or anything, mostly because I dont want to have to keep taking my shoes off when going between finished and unfinished areas of the house.

For lighting, I'll have the four cans you can see in the pics (1 GE zone), plus 4 more cans across the back (2nd zone), rope light behind crown moulding at the bottom of the soffit (3rd zone), and 5 4-inch cans lighting the screen in the front (4th zone). In the bottom picture above, you can see the early wiring roughing in for the GE -- I used two metal boxes to make all of my connections and will run 1 neutral, 1 ground, and hots only to the GE box, which will be mounted in the face of a column.

Making progress, slowly but surely . . .

It's been a while, time for another update. As you can see in the pics below, I have painted the ceiling, finished my hvac, etc. And most importantly, I built dual IB subs into the front corners of the room. Each sub has 2 Fi Car Q18 drivers, and they are all powered by a Behringer EP2500 residing in the equipment closet in the rear of the theater. I have tested them out with music, no movies yet, and so far they sound AWESOME. They were a little spendy compared to what I had planned to spend on a sub, but they were definitely worth it. I was a little nervous about the wall flexing, so I braced the outer walls with 3 "shelves" of 3/4" OSB attached to 2x4's running along the inside of the perimeter of each sub; these "shelves" have 2 24" diameter holes cut out of them so that they add rigidity without creating little compartments within the sub. If anyone's interested in pictures of this (kinda tough to explain) let me know and I'll take some next time I crawl inside one of them. Anyway, my nervousness about the walls flexing was unfounded, it appears that the bracing worked and while the walls vibrate, they don't flex and I don't anticipate these things tearing themselves apart.

You can also see that the floor of the pit is finished, I just have to face the stairs with plywood and then I'll add some concrete floor leveler to smooth everything out before carpeting.

Ceiling looks good, it's painted black, but the wife decided she wants a star ceiling so there went a gallon of black paint and $500 drywall finishing all-for-naught. Oh well, the star ceiling should be cool.

The flex duct running up behind the screen goes into the next room over and joins the line coming off the furnace (above the right-side sub). I have a duct fan on this one, and both this line and the line from the furnace/AC are on smarthome dampers which are setup such that one line is open while the other is closed, and vice versa. That way, I can bring AC in in the summer, but in the winter I can close off the theater from any direct heating and circulate fresh air from the adjoining room. If that makes any sense. Anyway, pictures - first from the entrance door, and then from the equipment room door in the other corner -

One more pic - here you can see 2 of the large fabric frames that will go along the walls. I've trimmed the room out in maple plywood (the fabric frames will cover the ply edges) and you can see where one of my columns will go where the two strips of maple run vertically up the wall on the right side of this picture. Between that column area and the subwoofer are the two frames. Made from 1/2" MDF sandwiched on 1/2" OSB. The area below the OSB cross-piece is 4 feet, perfect for applying my rigid fiberglass under (the place I sourced it from carried OC "QuietR" so that's what I'll be using). I haven't decided yet whether I'll bother with the poly batting on top or not. Any thoughts on whether that will actually be necessary to keep the GOM even?



Next steps include finishing the paint job in the equipment room, building the frames that will cover my subs and the screenwall, applying acoustic treatments, facing the steps, and levelling the floor. THEN I can carpet. I'm motivated right now as I'm psyched over the new HD80 and HC4900 1080 pj's -- I think one of those is going to have to end up in here and I am impatient!

Thanks McCall -- where did you get your poly from? Do you know if there is any certain type of 1" ploy that is better than others?

Wow, lots of replies all of a sudden. Yes, this thread is desperately in need of an update -- I've been so busy doing work on the theater that I haven't slowed down to update the thread -- or take many pictures, for that matter. I will update tonight. Screenwall is up, much of the fabric frames are up, carpet is in, seats are in, PJ is hung -- it's a few weeks away from being done but it looks like a theater now. Stay tuned.

As for the pit, my house is built on straight sand, used to be potato fields all over in my town, so we don't have any water-in-the-basement issues. torrential rain outside = bone dry inside. As far as moisture in/from the concrete itself (which really is no different than the rest of the basement), I consulted with the building inspector and finished the pit according to his direction -- poly vapor barrier on the bottom and any wood that contacts even the poly is treated (just to be doubly safe). If I had it to do over, would I recommend doing the pit as opposed to a riser? I questioned it mid-build, but now I'm glad I did the pit. I thought starting out that the pit would be cheaper, but I probably spent as much or more finishing it out than I would have building a riser. No need to fill a riser with sand though, at least. Nevertheless, I had to have the door in the rear of the room, and I didn't want to have the step up to the riser right inside the door. Plus, I was able to go with 8' ceilings throughout the basement without losing headroom in the theater due to a riser. Now that it's almost done, I'm glad I did it this way.

And yes, I definitely took up some prime bass trapping space with subwoofers. (Am I the only one that finds this ironic?) I have acoustic cotton stuffed in the rear soffit corners, which admittedly isn't thick enough to do a heck of a lot, and then I have floor-to-ceiling 16"x24" cotton triangle traps in each of the front corners behind the screen (i.e., the corners made by the front wall and the screen-side edges of the subwoofers.) I haven't taken any measurements, but I don't find the bass to be too boomy or otherwise offensive, so hopefully the front corner trapping and the stuff in the soffits are doing some good. It sounds good to me right now so I have no intention of changing anything -- perhaps ignorance is bliss on that.

Okay, here's a couple pictures. Now I know what people mean when they say its tough to get the colors to look right -- everything looks so dark... if I was smarter about using my camera I would increase the exposure time but I don't know how to do that. Time to read the manual.

Anyway, here's a shot of the front of the room from the entry door:



And here's a shot of the rear of the room. In this one, you can see one of my half-finished columns, as well as the new HD80 and Aussiemorphic lens.



BTW, Aussiemorphic lens = awesome. I highly doubt that I will ever upgrade from it even if I won the lottery. I haven't seen any other lenses in action other than a panamorph U85, which I bought when I was still planning on going with the VC lens and tested out on a friend's projector. So I probably don't know what I'm missing, but the Aussiemorphic seems great to me. For that matter, the HD80 is incredible too. This is the first digital PJ I've ever seen that looks incredibly sharp yet I can't see any SDE - "film-like" definitely applies, cliche' as it is. The SDE may be helped by the SMX, which already has a weave that may obscure any lines that are there, and of course the lens may be having an effect too. Anyway, that's the update... The finish line is in sight...

One other thing -- looking for opinions on what color fabric to use on the sides of the subwoofers. I have enough of both the red (it's actually GOM anchorage "mulberry") and the black (onyx) that I could use either one. I'm currently leaning towards black, as I think that will help to set the screen off, cut down on reflections off of that surface, and should create kind of a "shadowbox" effect. On the other hand, the argument for the red is that maybe it will look weird going from the red face of the sub to the black side on an outside corner like that. Like I said, leaning toward the black but if anybody has a strong opinion one way or another I'm all ears. I may end up just making one of each color fabric panels and putting them both up to see which one I like better.

Thanks Cathan. Yep, the trim is plain maple with a few coats of satin poly. BTW, I don't think the internal IB pics are going to happen -- I had planned on crawling back in there to screw down the fabric panels from the back side, but I got lazy and shot the air nailer into them. Can't see the holes at all. Now my bass traps are covering the access panels... If you want I can draw a picture of how the bracing works and post it though. Let me know.

Yeah, the directors are two rows of four. MKII was super easy. I am leaving it in place for 16:9 material (will just go to 4:3 on the PJ) so didn't need a slide -- just screwed it right into the ceiling. That meant the lens was a little high so I re-drilled holes lower on the bracket than where Mark pre-drilled them, but that was no problem at all. The only other comments on the MKII setup are 1) make sure its as close to the PJ as possible, and 2) it's much easier if you center and size the 16:9 image before trying to incorporate the lens, so you're only dealing with one variable at a time, and 3) if you're doing a DIY screen and going to frame it, get the lens and PJ set up first and then frame from there. That way you can measure exactly how far from the top and bottom you need to be to deal with pincusioning, and you can also bring the sides in far enough that the slight band of CA (maybe 1/4" ?) on the edge of the screen will fall on the velvet of the frame and be invisible. I had enough pincushioning that my screen is actually a tad over 2.40:1, but the image fills the whole screen on all sides.