Bluffs Cinema Construction Thread - a Dennis/Pro Theater DIY build

Hi all - welcome to my home theatre build thread!

Some background - for the last 4 years at my previous house I have been happy with my home theater 1.0 - a well performing but spartan and small room (18'x12') really only big enough for 2-4 people. Ceiling height was limited at 6 feet, so tiered seating was not possible. This year we moved to a larger house in eastern Toronto - an area called the Scarborough Bluffs:




Now I have a basement room that will serve as a much better starting point for home theatre 2.0, and so the Bluffs Cinema is born!

The raw dimensions of the room are approximately 28' x 13' x 6'8". The length of the room gives me lots of flexibility for multiple rows of seats, as well as to have a deep stage at the front of the room to put speakers and substantial room treatment behind the screen. Room width and height are still limited,
but to improve the latter I am going to do a partial dig of the room, lowering a portion by 1' effectively creating the "stage" and "riser" out of the existing pad. This is going to be a significant cost and challenge but I think the payoff will be more than worth it.

The initial configuration of the room will use a lot of my existing equipment and furniture, including:
- 108" wide 16x9 DaLite High Power electric screen
- JVC RS1 projector
- PSB Stratus Gold tower speakers
- Berkline HT loveseat with electric recline

At some point in the future (perhaps the following year) I will be upgrading to 132" wide 2.35:1 acoustically transparent screen and a brighter projector to drive it. Oh, and D-Box motion for at least 2 of the seats

I am enlisting the services of Dennis Erskine and his team through the AVSForum Pro Theater Layout Service, so I should be documenting that process so others can get an idea of what he is offering at this great price point.

Here is my initial design for the room (done in Google Sketchup) - This is before Dennis has done any work on it:





And here is what it looks like today!:




Here are some of the home theatres that I have drawn a significant amount of inspiration from:

First things first: The Dig. Some of the challenges I will face for this part are:

• Benching vs Underpinning: I am going to leave a 1' bench in order to greatly reduce the cost of this lowering. Also, I am a little skeptical about underpinning in general - too much opportunity for things to go wrong. I think the bench wall ties into the design fairly nicely as well.
• Drainage: it remains to be seen if the existing drainage is low enough to be tied into the lowered pit - if not a sump pump may be necessary for this section. Also I may do some interior waterproofing along one of the long walls because it is adjacent to the garage and exterior waterproofing is not possible. Tieing this all together has some complexity to it.
• Asbestos: under the carpet in this room is a mastic residue (also known as 'cutback') from old 9"x 9" vinyl tiles, which typically contained asbestos. Sometimes the mastic did as well. I have sent samples out for testing and if they are positive then the mastic will need to be removed (by asbestos abatement pros) in the area to be dug before power tools can be used to break up the pad.

So once Dennis and I agree on the correct dimensions of the pit, its off to the engineer to drawup blueprints and pull permits. I am planning for the dig to happen sometime in January, which gives me lots of time to think through other issues, such as Soundproofing, HVAC, Electrical, etc.

Time to finally update the thread - construction has begun!

Here is what the room looks like now - excavation is fun (well its a little past - we have put in the sump pump)



Contractors have excavated the lowered area and are ready to pour the bench walls on Monday. Asbestos in the cutback residue turned out to be of minimal concern - I talked to 3 asbestos abatement companies and they all suggested not to bother removing it - they would be using a chemical peel that doesnt do that great of a job anyways. Just for my own curiousity I had some several dust residue samples tested and they came back negative for asbestos.

Drainage issues have been more of a challenge than I expected (or at least hoped). The exterior weeping tile for the house enters the house at the front of this room. As expected it was completely clogged (50 year old clay tiles). Since we were adding a sump pump for the lowered section we decided to drain the weeping tile into the sump also (since the existing path must be almost non-functional anyways). However now, even in the dead of winter, the pump is turning on every hour, and my driveway is a giant ice sheet from the discharge water So now we have to rethink this a bit. Now I hope to be able to tie the weepers back into the existing drain system, but to do so we will need to either clean out the inside weeping tile or dig it up and lay down new pipe, which would mean busting up a trench to the adjacent room (where it ties in with the storm drain)

Either way the contractors should be pouring concrete this week. It certainly is nice having the extra foot of ceiling height in a large portion of the room!

Next steps after that should be:

- Put down Delta-FL or similar across the entire floor
- Sprayfoam insulation
- Framing (leaving a gap between the sprayfoam and the stud walls for decoupling)
- Modify HVAC for better soundproofing potential
- Hang hat channel and clips inside joists to maximize finished ceiling height
- Rerun electrical
- Drywall (DD + GG)
- put down subfloor

After that, the actual theater construction can begin!

Oh yeah - maybe a little too interesting I'm sure most of the workers think I'm crazy but at least the foreman thinks its going to be awesome!

I think I may have found someone to clean the existing weeping tile with a hydrojet - we'll see tomorrow. The cost isnt all that much cheaper than just digging and replacing it but at least I wont have to rip up the carpet in the adjacent room to get at it.

In order to do a bench wall you need preserve a 7/10 slope (10" run for 7" rise) by code in my area. So the benches are approximately 1.5 feet wide in order to lower by 1 foot. However after I finish the space (insulation, air gap, stud walls, double drywall, sound treatments, fabric) the remaining bench walls should be just slightly under 1 foot wide.

I am planning a 6.1 surround at this point, and the L/R surrounds will be mounted in the soffits, while the C surround will be mounted in the cabinet at the back. I decided against columns simply because the room is narrow enough as it is, and I feel that columns will make it feel somewhat claustrophobic. I may change my mind as the room comes together though.

Dennis has completed my plans - I will post them here sometime this week. (Dennis doesn't have a problem with me doing so and neither do I) My plans didn't change all that much - he mostly validated my dimensions for the excavation, and gave me a good recipe for sound treatments for the space.

Cheers

Lotta mud at the moment!

Coming along, here's what it looks like now. The pad is being poured tomorrow!

The lowered area is now completed - spray foam is next, hopefully this week:

Mainly because the open half of the back wall will be a convenient spot to stuff overflow chairs for big events - I don't really want to stick a speaker there right behind someones head.

I could always change my mind in the future since I'm not pre-wiring anything A/V related. The soffits will allow me to run wiring around the room and if need be I can always run a wire downwards behind the fabric walls.

I think a pair mounted in that fashion would be too close to the regular surrounds to distinguish themselves.

Just curious - where did you read that? I would think a single center would localize better (as being behind you) than two. Otherwise wouldn't the front center also present the same issue?

7.1 mixes down to 6.1 pretty well - collapse stereo to mono and steer a little bit of the directionality to the 2 surround channels.

With a 9' wide screen (10.5-11' acoustic transparent in the future) the front row will be something like 12-13' and the 2nd row is something like 18-19'. For me the ideal position would be somewhere in the middle of those two but putting a row there meant the other row would be way too far ahead or behind. So I consider both rows prime viewing locations

The screen is to be approx 3' forward of the front wall, giving me lots of room for speaker placement behind the screen, as well as electronics and acoustic treatments.

I'll try to post the Dennis plans tonight

Okay here's what the plans Dennis constructed for me look like:





One thing to note: Dennis specifies Quest products for the acoustic treatments for the designs. I have not yet requested a quote from him for the treatments, but I dont expect them to be cheap Nor are Quest products readily available from many sources. The website is incredibly sparse also. Nevertheless Dennis can supply measurement sheets for these products and they are impressive. He also suggested to me how to make homemade versions of the Q-flector and Q-sorber products. The Perf-Sorber has a custom perforated membrane in front and can not be DIY approximated.

I'm thinking ahead to some of my electrical layout and I had a couple of questions:

1)with fabric walls and 2" think acoustic treatments, my panelling will need to come out 2" to be flush with the rest of the wall. This seems like an opportunity to use surface-mounted (to the drywall) electrical boxes instead of regular boxes, and avoid those holes in the wall - better soundproofing.

Has anyone else done this? What boxes are recommended? Are there fire-code issues?

2)I will be using ropelights and puck-style pot lights in the soffits - what are the current recommended brands? Is it recommended to go with low-voltage lights or regular LED GU10-style lights for the potlights? I plan on tying them all together with a Grafik eye type system.

Thanks!

I think the wiring would still be behind the wall, it would just poke through the drywall to the boxes - a tiny hole that can be caulked or filled with putty.

You wouldn't even need an acoustical sealant (which never fully cures) to fill up these holes - any old caulk or hole filler would do (subject to fire-code regulations)