Our family Home Theather project actually started by in 2005, when we built our house. I was already thinking about a nice media room in the basement, and the very first thing I did was ensure that the basement ceiling height was 9 feet. While not knowing back then that a dedicated HT would be our direction, I at least knew that I didn’t want a finished basement that had a low ceiling.
After we had lived in our new house for about a year, I started planning how to finish the basement, and this was about the time I started thinking about doing a dedicated room, and about the time I started looking around on different forums. I’m glad I thought about this before starting the basement since going with a dedicated room meant special considerations needed to be taken before even starting the framing. I spent the next couple of years finishing the rest of the basement, so that our oldest son could have his own bedroom (the basement work changed our home from a 3 bedroom to a 5 bedroom), and so that we could have a playroom/exercise room. During this phase of the theater project, the theater room was framed (wall within a wall construction), all plumbing was moved to the other side of the basement, along with some other prework. During the winter of 2010/2011, the rest of the basement was finally finished, and the theater construction was ready to begin...
Phase 1 – Constructing the Outer Shell of the Room: Framing and Soundproofing
The first phase of building the theater was to ensure that I ended up with a soundproof room. Otherwise, I’d be facing a daily “Turn it down!” from my wife. Also, as I was finishing the rest of the basement first, I wanted to make sure I didn’t do anything that would cause me a bunch of rework. This meant that I needed to do all my soundproofing research before I started framing any of the basement.
For the walls, I chose to go with a room-within-a-room design, consisting of two 2x4 walls side by side with 1” gap in between. Both layers contain full layer of R-14 insulation. Finally, the studs were covered with double-thickness drywall on exterior wall and single-thickness on the interior wall. In addition, in order to ensure that there wasn’t any gaps within wall structure, the small exterior window was framed in with easily removable, but thick and soundproof, frame with handles. As the electrical wiring was installed, we ensured that no electrical wiring penetrated both walls, ensuring a gap of air between them both. Finally, a heavy-duty steel door completed the soundproofing from the wall perspective.
For the ceiling, we got lucky from the standpoint that our house was built with heavy-duty 2X12 floor joists, as opposed to the smaller composite joists. These were each stuffed with two full stacked layers of R-19 insulation. There are two air ducts in the ceiling, feeding the upstairs. These were both wrapped in sound-deadening acoustic material. The final touch on the ceiling sound proofing was double thick drywall.
In all, the soundproofing works fairly well. With the door closed, at near ear-splitting volumes on the inside, practically zero mid-to-high frequency sound escapes. However, some low frequency bass does escape, not into the basement, but into the upstairs. The sound leakage isn't so bad - only low-end and not very loud. One way to describe the sound is, that at these high volumes, someone sitting directly above the room would wonder if there is distant thunder and (if the person doesn’t know there is a theater cranking below them) they will actually ask if there is a storm coming (this has happened multiple times, and is actually pretty entertaining). The rumbling isn’t anything loud enough to disturb conversations, but it is enough to notice. Looking back, I believe that this bass leakage could have been prevented by extending the “room within a room” concept into the ceiling as well. However, I did not want to give up any headroom, so I will just live with this small inconvenience. And, as a side note, it helps me ensure that my kids aren't cranking the theater to unsafe levels for their ears while I'm upstairs.
Phase 2 – The Floor
Once the room was drywalled, floor-to-ceiling, the next step was to build the floor infrastructure. Completing the floor consisted of building a 15” high riser, a stage, and plywood flooring for the middle of the room where the theater is at floor level. These structures are where the first acoustic treatments were applied. The design of the riser and stage came almost straight from damelon's theater, with a few tweaks to match my room.
The riser was constructed with 2x12s, and topped with two layers of ¾” plywood. It was filled with R-38 insulation for bass absorption. It is isolated from the walls with ¼” thick foam, and isolated from floor with roofing paper. It also had electrical run through it, both for step lights and for an outlet to be placed on the front of it.
The stage with filled with 1.5 tons of sand, which was an important aspect of bass absorption, since the subwoofer would be sitting on the back of the stage behind the screen. And, yes, I carried the sand downstairs one bag at a time. During the entire project, there was a lot of different things that were done in that basement, but I must say that pouring sand into that stage caused the dustiest mess of all. (and on top of that you need to wear a mask because sand dust is VERY harmful to your lungs).
The stage was also isolated from the walls with ¼” thick foam, and isolated from the floor with roofing paper. It was then covered with ¾” plywood, and cut and routered so that it had a nice overhanging curve.
In between the stage and the riser, the floor was not left as open cement. Sheets of 4’x8’ plywood were installed, and isolated from floor with roofing paper over Platon plastic ‘raised bubble’ sheets to provide adequate ventilation.
Phase 3 – Columns and Soffits
With the floor complete and ready for carpeting, the next step was the columns and soffits. The columns were to contain speakers, electrical outlets, light switches, and a ‘hidden’ HDMI input (so I could plug in my iPad and rock out or plug in a video camera without needing to access the rack). Also, I was finally starting to build things that would be visible and part of the finished product, so I had to start being very careful. Even with this forethought, there were plenty of things on the columns and soffits which I needed to re-do because either I had made a mistake or I wasn’t happy with the results.
The soffit system contains all of the lighting for the room, a series of can lights on two separate circuits (one for the front, one for the back. It also contains a blue rope light, which runs around the entire room, and shines a backlight onto the ceiling. Within the soffits, electrical PVC was run to each column location, and these pipes serve as the pathway to run all the speaker wire and HDMI for the projector. Finally, the bottom of the soffit was stuffed with R-13 insulation to help with mid- and high-frequency sound absorption, and then covered with black GOM fabric.
Phase 4 – Screen Wall and Wall Coverings
The final phase of the project involved building a wall for the screen, which would also serve as the wall for the hidden room which contain the rack, the front and center channel speakers, and the sub.
Also, during this phase, the front wall was covered with 3.5” recycled denim for sound absorption. Recycled denim is a great, cost-effective solution for this, as it has nice acoustic absorption properties, is fire-retardant, and also doesn’t cause skin irritation like fiberglass insulation does. This was important since this treatment was to stay exposed on the wall.
The side and rear walls were covered with homemade panels. The panel frames were constructed of strips of ¾” hardwood plywood, glued back-to-back, making 1.5”-thick panels. The 45-degree angle was mitered in, the frame pieces were glued together, painted, and then GOM fabric was stretched and stapled over the frame. Within each frame is a piece of ½” thick carpet padding, which serve as acoustical treatments for the walls. The treatments are not the same size as the frame; rather they are somewhat smaller. This ensures that some bare wall is exposed to the sound, keeping the room from becoming too ‘deadened’ acoustically. I'm sure I will receive some comments related to going through all of this effort to build a nice theater, only to use carpet padding as my final acoustical touch...which is fine, but I just couldn't justify the cost of high-end panels when, to my ear, well-placed sections of carpet padding do the job just great.
The final touch was the screen, and the panels surrounding the screen – which are removable providing easy access to the rack and speakers behind.
The final room dimensions are as follows:
- 25’11” x 14’6” (full size – includes false front wall)
- 23’1” x 14’6” (usable area – screen is front of measurement)
- Height at highest point (middle of floor) – 8’10”
- Riser Height – 15”
- Stage Height – 12”
- Screen Size – 48” x 112.8” (2.35:1) format
- Distance from Screen to Front Row eyes – 141”
- 2 Emotiva XRT 6.2 Tower speakers
- 1 Emotiva XRC 6.2 Center Channel
- 4 Emotiva XRM 4.1 Monitors
- 1 Emotiva Xref 12 Subwoofer
- Emotiva UMC-200 Preamplifier/Processor
- Emotiva XPA-2 Two channel amplifier (mains)
- Emotiva XPA-5 Five Channel amplifier (center and surrounds)
- DirecTV DVR
- HDMI input jack on front left column
- Panasonic PT-AE8000U 2D/3D Projector with CHIRPAU Projector Mount
- Custom sized, Acoustically Transparent, High Contrast, Audio Vision Da-Lite Screen - 48"x113"
- Emotiva CMX-6 Power Distribution
- Logitech Harmony 1100
- Starcase Rack (60" tall x 25" deep - steel, with casters)
Anyways...that's it for now...please let me know if anyone has any questions...
Thanks again to everyone on this forum whose willingness to share made this build go very smoothly. It was a lot of work, but well worth it!