Harrods View Theater Construction Thread

Hi,

Before I begin, I want to say thanks to all the people who have shared their insights, knowledge, and ideas in AVS. Some of the results are truly spectacular and have really helped inspire me.

I intend to use this thread as a means to document my build. I will post photos, detailed descriptions, material usage, etc. Please feel free to add any comments or tips along the way. Feedback is always welcome!

Here's a little more info on how I got to this day:
I started dreaming of building my own home theater about three years ago after witnessing an incredible home theater in Louisville, KY. It has taken me a little time to reach the starting point - primarily because I needed to convince my wife that this was a good idea. Eventually, I struck a compromise with the missus. I agreed to remodel the entire basement before finishing with the theater. So I gutted the entire basement, installed two LVL beams to open up walls, moved shower and toilet drains, remodeled the bathroom including tiling with travertine stone, added a fitness room, added a guest bedroom, added a billiard room, and three closets. Now 2.5 years later, I'm ready to move on to the theater - long overdue!

Our theater will be constructed as a dedicated room in our walk-out basement. I plan to use construction techniques to provide isolation from structure-borne and air-borne sound (room-within-room). I will have a dedicated equipment closet outside of the theater under my stairway.

SUMMARY

Location/Dimensions
Dedicated room in walkout basement with finished dimensions of 14’-6” x19’x 9’.

Construction
The theater will be a room within a room.

Front and left exterior walls are poured concrete. Right exterior wall is stud load-bearing wall. I will build 2x4 walls inside of these three walls. Back wall will be staggered stud wall. RSIC DC04 clips will be used to decouple these walls from the floor joists above. There is a window in the left wall. I plan to plug that window but make it still accessible for any future maintenance.

Ceiling will be framed using independent ceiling joists – not attached to anything other than the right and left interior theater walls. Ceiling and walls will be 5/8”drywall + Green Glue + 5/8” drywall. I may also incorporate a fiber optic star field.

Floor/Stage/Platforms
Sub-floor will be constructed using a floating plywood subfloor over concrete floor - 1” thick. There will be a sand-filled stage directly below the viewing screen. Two additional platforms will be situated in the rear theater corners for rear seating. These platforms will be insulation filled.

Entry
Two custom entry doors each 3’ wide by 7’ high. Doors will be thick – three inches and heavy. Because they are double doors, sealing them will be an interesting challenge.

Heating/Cooling
Theater will be connected to the lower HVAC system. Forced air system – supply and return will be treated using flexible acoustical ducting (not the plastic lined variety – this ducting has special lining to promote air and sound interaction with insulation). Sheet metal trunk will be wrapped in insulation and ½”+gg+½” MDF. It will be built outside of the theater drywall perimeter. Additional supply and return plenums will be built using 1” duct board. I plan to use a 4” x 36” linear diffuser for supply register.

Seating
Seating Four Berkline 450004 seats in first row with raised seating in second row. Four seats in second row.

Screen
Screen 130” 2.40:1 acoustically transparent screen. DIY frame using Seymour AV CenterStageXD material. I plan to build a Constant Image Height Masking system to accommodate 2.40:1 thru 4:3 screen ratios.

Projector
Likely Panasonic PT-AE4000U (will take advantage of the zoom feature for Cinescope formats). Not sure if I want a hush box. Welcome input on this.

Speakers
I will build an 7.2 Surround Speaker System. All speakers including the subwoofers will be designed and built by me. I will be using passive crossovers constructed of high quality capacitors and inductors. My design work is already done, when I reach the build stage, I will you show you how I did it.

In case you are interested - the LCRs have been designed at 63Hz-20kHz flat response within .5db from 80Hz – 20kHz. The -3 point is at 63Hz. Sides are similar, flat from 80Hz – 20kHz and -3 at 72Hz. I plan to cross the subs at 80Hz.

Lighting
Recessed lighting in the soffits. LED rope lighting in the ceiling trays. Sconces – probably not. Led step lights marking platform. Possible Fiber-optic star field on ceiling.
Lighting Controller -Grafix Eye 3506 - 6 zone programmable controller. Reusing one that I already have.

Acoustical Treatments
This is where I will need the most help. Currently planning 4 – Floor to Ceiling Superchunk bass traps in each corner. Soffits will be stuffed with acoustical cotton and bottoms covered with GOM fabric. Broad band absorption on the screen wall using 1” Linacoustic floor to ceiling. Broadband absorption on early reflection points. Maybe Diffusion on rear wall. Will welcome input when I get to this stage of the build.


Let me know if I’ve missed anything.




MASTER FLOORPLAN


TOP-DOWN PERSPECTIVE
Shows seating locations, platforms, speaker locations.

I am thinking about two in-wall subwoofers. One each in the middle of the side walls. Any opinions about that idea? THX.com suggests placing sub in the middle of opposing walls – that’s where I got the idea. Historically, I’ve put subs on front-wall, which works ok.

Note: Equipment Room is intentionally omitted.



Planned Viewing Angles

Here are some pictures of the theater space after ripping out the existing drywall. You will notice the HVAC trunk along the right wall. This will need to be moved because I plan to install 2"x6" ceiling joist between the existing floor joists. Still need to remove insulation and framing on front and left walls - that will complete the rip out.

Front wall after drywall tearout


Left wall after drywall tearout



I'm planning to move the HVAC trunk, then wrap it in insulation (2-3"), and enclose with mdf. Here's a Sketchup of my plan.




BTW - I've had some email exchanges with Ted White (very responsive guy). He gave me some really good information and advice on treating the HVAC. The supply inside the theater will be handled by building a separate ductboard plenum as shown in the plenum box picture below. The supply plenum will be fed from the sheet metal HVAC trunk via 15' feet of acoustical flex duct. See picture below of the product I will be using.




Flex Duct
Purchased from JPL. It is 7" duct. Comes in two pcs 7' long each. The lining is what makes it better than standard home depot flex.




Well that's probably enough posting for today. Next step - order supplies for the build.

Thanks. I'm definitely looking forward to moving forward with this project.

Hey Ted - I appreciate the comments.

Not completely married to to the double-doors, but wife does like them.

Here's what I was planning to do - would love your feedback.

In general I find that doors are problematic to deal with- especially wood ones -wood moves, seals fail. And to your point, the problem is worsened with double-doors. To mitigate this I was planning to build custom doors with 3-layers 3/4" MDF with GG between Layers. I then planned to veneer the outside layers with hardwood panels that I'll make in the shop. Total door thickness between 3.5-4". By design I planned to utilize an overlapping joint (shiplap) where the doors meet in the middle. The joint would conceal two seals. The receiving door will have upper and lower bolt locks to stablize the intersection of the two, when the theater is in use. Of course seals all around.

What do you think about this approach? Could it effectively mitigate sound leakage concerns?

If not, what would you recommend? Am thinking you will suggest one door, but where in the design. Entry has to be on back wall.

Finally, the right wall (one with stairs connected to extior wall is planned for double stud. The back wall is staggered, but is not connected to stair wall in way. Is that ok, or am I missing something?

Thanks

Thanks guys for the feedback.

Using this forum to post ideas and get feedback has already paid dividends. I shared your comments with my wife and "homerun" - we are dropping the double-doors.

We're going with single door in one of the backwall corners. This will allow for a much better second row, pulling seats out of corners. I too disliked the seats in the corners, which I accepted originally accepted because I knew I would never be sitting there.

I'm going to spend some time this morning reevaluating the backwall taking careful measurements. Double stud wall may work, but I have some critical dimensions that I need to hold in the billard room. The pool table requires a room 17' long. Moving the backwall deeper may make the billiard room length less than 17'. So it may have to stay as staggered stud.

I'll post revised drawings as soon as they are completed.

Ok now that I'm revisiting the plan to eliminate dbl-doors, I'm questioning use of in-wall speakers. What do you guys think?

Factors:
I want two rows of seating
Room is 19' long.
I'm know I want spkrs behind the AT screen.

Thoughts:

I could keep surrounds in-room rather than in-wall. That would be easy enough. But inroom LCR is another issue.

Most screen walls appear to be designed at least two feet in front of the in room speakers. That would make my room about 17' in length. That just feels too small to me for two rows.

Do you think in-wall LCR's with damped backboxes will be ok (saving some floorspace)?

Yesterday I spent some time taking careful measurements of the rough space.

I concluded that the back-wall can be moved out toward billiard room by 7". This will allow me to build the back-wall using double-stud technique. I will still have the minimum space needed for the pool table. So I'm pretty thrilled with the outcome.

As I mentioned, we have decided to eliminate the French Doors and go with a 32" entry located in the back right corner. Because we can go with double-stud back wall, we will take Ted's recommendation and use dbl-doors. Eliminating the double-doors will also allow for proper back row of seats.

Ted - can you point me in right direction to understand how to seal the doors? I'm also curious about the door jamb - should it be continuous or break with each stud wall?

I've also changed my mind on use of in-wall speakers. I've decided to incorporate columns and bring all the speakers in-room. Surrounds and subs will be hidden in columns. My idea is to build the speakers with narrower depths (as would be the case with in-walls); however, rather than place in the wall, I will place them in the columns. The columns will also allow me to meet electrical code requirements because I can place the outlets in them without electrical box penetrations in the walls.

Today, I plan to order materials and work on the SketchUp model of the theater. I'll use this time to work the details on the columns.


Here's the new the master floor plan (using MS Visio).
Note: it doesn't reflect column placement yet. Plan to have columns for surrounds, subs, and on side walls near the front to provide some symmetry.

Thanks. I think it has solved a lot of design problems - improved sound isolation and much better back row. Can't wait to start building!

Thanks for the suggestion.

I do plan to spend more time analyzing speaker placement.

I started out thinking I would follow THX recommended placements. THX 7.1 calls for two side-by-side direct firing spkrs as rears. Frankly, I'm also debating placement of subs.

Anyway, I do need to figure this out soon as it will dictate the outcome of spkr and column placement. Need to know where wires will be pulled before drywall goes up.

BTW - Are you aware of any good online resources regarding Toole's views on setup? How's the weather in Sydney?

Tx

Yes it will be true room-within-room design, even ceiling joists will be independent from floor joists above. HVAC will be treated with flex duct and ductboard plenums.


I'm concerned about the door swing issue too. My feeling is that code will require the door(s) to open into the room as you point out.

Bottom-line: I plan to check with the building inspector and have plans reviewed/approved before starting. Hopefully I'll get that accomplished within the next week or so.

Wow that's toasty. We're about 20 degrees F, which is a little colder than usual for us Louisville.

BTW - I wanted to let you know that I found some more information on Toole's research. You might be interested as well.

Here's a link to three pretty good articles.
http://www.infinitysystems.com/home/...nf-rooms_1.pdf
http://www.infinitysystems.com/home/...nf-rooms_2.pdf
http://www.infinitysystems.com/home/...nf-rooms_3.pdf

Thanks for the info. After doing a bunch of reading last night, I've determined that I will move the rear speakers into more standard arrangement - consistent with Toole's and Dolby recommendation for 7.1. I'm still spending some time researching the placement of the subwoofers.

All indicators suggest I should use two subs - one for sure on front wall, but not clear yet about the second. This will be my next area of focus.

Once I have the final speaker placements sorted out, I'll post an updated plan master floorplan.

Appreciate you guys helping me out!

I checked out your build - the back boxes look substantial!
I'll keep an eye on your build. I'm looking forward to hearing about your experience with them. They look like a reasonable compromise to minimize sound leakage.

Anyway - since I've determined that I can move my back wall, I have more room depth to work with. So I'm going to go with in-room LCR. I've taken careful measurements and can make the two rows work quite easily.

Good luck on your build. I'm looking forward to your progress updates.

I've placed first order from HomeDepot for materials today - $1700 for lumber (walls, ceiling joists, platforms, and stages), mdf, plywood (for subfloor), insulation, drywall, sill sealer, and delivery charge.

Will be delivered on Friday. I plan to take the day off to receive delivery and get started.

Also will be ordering Green Glue, Acoustical Caulk, and putty pads. Expect that to cost around $800.00.

I have an existing 2x4 stair wall- right wall. Studs are mostly 12 OC because it is load-bearing wall.

Exterior face is covered in 1/2" drywall. The interior face is ripped out. I plan to build another decoupled 2x4 wall on the interior to create a double stud wall.

Before putting up the new stud wall, should I add Green Glue +5/8" drywall to the back side of the drywall on the existing stair wall to provide more sound control?

Adding another layer is not possible on the stair side. The trimwork is too extensive and am just not gonna go there - too much work.

Here's a picture of the wall I'm referencing.

Here's the latest floor plan with speaker column placements. I'm now working out lighting and wiring diagrams.