Help me design my home theater - planning stage - Page 5

Because, Craig John (a contributor to these forums) told me that if your feet are on a concrete slab you dont get the full tacticle response - your body is out of synch with your feet. A raised platform addresses this discrepancy.

My 2nd design for the rear seat riser. This time, incorporating a bass trap design. The riser will butt up against the rear and side walls. The idea is to create four cavities in the riser in the ratio of 1:2:4:8 volumes. Each cavity will be separated by a floor to deck joist with no air passage allowed between them. Within each cavity the deck joists will have an air gap from the floor. I will install 4x14 standard air registers along the walls to let the low frequency waves in to the bass trap. Will this work? (see attached picture)

 

Riser Design.pdf 175.4873046875k . file

Point well taken. Even when I was in graduate school I was not particularly good at solving partial differential equations. Today, I don't stand a chance.

I have converted my design to a single large partition using bar-type long registers. See attached.

(While I knew that resonance is a function of volume, not surface area, I provided the latter because I figured that it is more easily understandable).

Thanks.

Now, I have to correct some past mistakes. I had not thought of a riser going all the way to the rear and side walls, but to be an effective bass trap, it must. I will remove the baseboards that I had installed - hopefully easy because the finish nails were driven into two layers of drywall.

 

Riser Design ver. 2.pdf 173.283203125k . file

Dennis:

Only the perimeter of the riser has joists from decking to floor. The inside joists are shown by broken lines in my last post and they indicate joists that extend only partway to floor. That's the right way to do it, correct?

Thanks

Built the second step of the stage and started framing the riser perimeter (2x12s)

I didn't understand this.

What type of cabiling should I consider for controlling my components (in another room, out of line of sight) from a hand-held interface at the front row?

Thanks. I will do this since my spans are nearly 11'

Here is my general acoustic plan from BPape:

"For the rear wall, if going to DIY - I would do 3 layers of 2" 703 covered with some 4-5 mil plastic before covering in cloth.

2" OC703 at the reflection zone. Same on the front wall (or the ECOSSE in any of these positions.)

Same 2" for the wall panels. Ideally, you'd do floor to ceiling on the side walls for the first 8' of the room from the corner then floor to 5' high for the balance of the wall."

Questions:
A) how to fasten 6" of 703 to rear wall? What to do with electrical outlets that will be covered? How to mount rear surrounds on 6" of fiberglass?
B) to minimize effort, I don't plan on fabric from floor to ceiling. if I use 2" furring strips and cabinet screws for fastening 703 to walls, then can I have a continuous 5' high fabric panel covering the side walls? (I plan to finish the top edge with trim.). Or will I need transitions to cover fabric seams?
C) how to make wides speakers be toed in inside columns?

Thx

Thanks! I didn't think of that. Great.

Big, instead of using 2 half inch plywood layers for the panel frames, would using a 2x2 with a half inch layer of beveled plywood be appropriate for a panel frame to achieve the 2" depth?

Any other options? Building up 2" using layers of plywood seems to be too labor intensive. Finished pine? BTW, I am planning to shamelessly copying the Bacon Race wall panelling technique.

Thanks or the tip. I might use Fabricmate if it is less trouble to install.

I finally finished my theater after almost 3 years of labor (finished the rest of the basement first!). Here are some pics:
Riser framed. Riser also functions as a bass trap. I left a 6" air gap at the rear and used R-19" unfaced insulation between the joists. The R-19 was suspended above the basement floor using plastic netting that I installed to prevent the insulation from falling through. The riser sits on roofing felt material. Used 3 layers of OSB: 3/4"+1/2"+3/4" with on tube of green glue between layers for each sheet.



Here are pictures of the stage: The cavities were filled with sand that I had delivered in bulk from a local supplier. The sand was wet so I let it dry for a few days in the sun, but it was a lot less expensive and more convenient than buying in bags from a big box store (which was also wet anyway). Total of 2 cubic yards of sand. I lined the stage cavities with plastic sheets. The stage was built the same way as the riser: 3 layers of OSB.



Once I built the stage, I built a false wall for the screen and in-wall subs. Below is the sequence of the in wall-sub installation:

First the wall is framed, the speaker enclosures installed (with green glue behind the enclosures), and the cavities filled with Roxul



Then, the first layer of 1/2" drywall and green glue...


...second layer of drywall...


speaker drivers installed, with 2" of OC703 fiberglass


And the whole thing covered with black muslin from Joann's Fabrics


I also put 2' on side, triangular OC705 on the left and right corners for bass traps

Construction details of my screen masking system using the details described in this thread




I plan to install Heights speakers and built platforms to support them




My soundstage: 3 Atlantic Technology 8200es, 2 Atlantic Technology in-wall subs, and 2 B&W 805 Matrix Heights


Screen frame being built. It is a 2.40 screen with 59" finished height


Here is the finished screen with Seymour Center Stage material (and daughter for scale)


I started the project with virtually no construction skills, but by now I was reasonably good with many trades...(including sewing...more on that later...)

DIY rack - Emotiva UPA-7, Denon 4520, Oppo BDP103, Atlantic Technology SA700 sub amp, and Tivo make up my gear


Bass shaker amps - Yung 200W sub amp from Parts Express. I find it provides more than enough power for the subtle shaking that one needs for a theatrical performance

Carpet installed. I used the following acoustical treatments:

2" 703:
- on front wall (stage to ceiling)
- on side wall, floor to ceiling for first 10 feet, and then up to 5' for the rest of the room

3 layers of 6" 703 (total 6") on rear wall (riser to ceiling) covered with 5 mil plastic sheet

front corners: 2' on side triangles of OC705 stage floor to ceiling (as mentioned earlier)

The whole thing was covered with GOM. I made the mistake of painting the room walls not realizing that I would need this treatment and will be covering with fabric
I made speaker columns using GOM and 1/2" steel tubes that I filled with sand.





Step lights

Sony HW50ES projector with ISCO III lens and DPI sled hung from an RPA Chief Mount Reading glasses for scale.


iRule interface on iPad3

Fusion Lagoon seats delivered by forum member 'RSH' (Roman)


Seats unpacked...


and installed in theater...


Aura Pro bass shakers installed under every seat

Opening night!!!