Home Theater of the Month: The Envelope

Like most DIY home theaters, this was a labor of love for its owner, who built almost everything himself, including the subs and screen.

Mike Rosinski (mtbdudex) is a prolific AVS Forum member with over 5200 posts to his name since he joined in 2007. I wonder how he could possibly have time for so much posting when he’s Manager of Engineering at the Nissan Tech Center near Detroit, MI, and he has a family with his wife and three kids, ages 9, 11, and 13.


Mike Rosinki’s family—and basement home theater—live in this beautiful log home.

Even more remarkable is his home theater, which he built entirely with his own hands except for the drywall and carpet installation. Mike’s primary goal was to balance the acoustics for all seats; as he puts it, “Every seat a good seat, but no single great seat.” His secondary goal was visual immersion, which he achieved by building his own ginormous curved screen that we’ll take a closer look at shortly.

Given his busy life, it’s no surprise that Mike’s theater was a long-term project. After two years of research, construction began in late 2004 and occupied his weekends for the next three years. “I had to pay as I went,” he says, “then it got more serious in late 2007 and 2008, when most of the build was completed.” Mike is quick to point out that he was finishing the entire basement at the same time, with a fourth bedroom, full bath, craft room, and rec room in addition to the theater.


This floor plan shows where every element of the theater is located.

In the theater, Mike used 2×6 wood sill plates and 2×4 staggered studs with insulation between them to form the walls. The back wall adjoins the hallway to the upstairs, so he had double layers of drywall installed on both sides of that wall for extra mass.


Mike is seen here hammering a stud into place with the help of his father.


Speaker and high-current wires run through the walls; Mike kept them at least two feet from each other for the most part, crossing at 90 degrees when necessary.

When he started this journey, Mike understood the importance of acoustics in a home theater, but not the specifics. “I knew in 2008 there was much I needed to learn in order to do it right, so I decided not to apply a cookie-cutter approach. Instead, I started with a bare-bones home theater and then add the appropriate treatments as I learned about them. Part of that decision was to use movable/hanging treatments, not the integrated type. That way, I could add them as needed and also easily do A/B comparisons.” For more on that, see this thread.

“My first acoustic treatment was making my second-row riser a broadband bass trap. The opportunity to do that arose when I discovered it wasn’t deep enough, so while I was fixing that, I decided to turn the riser into a bass trap, which is documented in this thread.

“Next, I decided to apply the RFZ [reflection-free zone] concept to the front soundstage for both rows of seats. I used ray-tracing software to determine where to apply the absorbers, and I verified the results with the mirror method and later with ETC [energy time curve]charts. I was very cautious to not over-treat the room; my goal was to apply treatments where they were specifically needed as determined by objective measurement and subjective listening.” This also led to several absorptive ceiling clouds.


This front-view screen shot shows where the first reflections from the front speakers are located, which is where Mike put absorptive panels.


Here’s a view of the first reflections from the side.

“Then, I added the rear-corner broadband bass traps, which I wanted to double as display shelves for the Star Wars and Star Trek stuff I’ve collected over the years, so they are my own design. I applied heavy craft paper to the front-facing portion, as I did not want to absorb too much sonic energy; rather, I wanted to reflect the mid-highs back into the space.”

Here’s a YouTube video of Mike and his corner bass traps:


In this view, you can see the right-rear corner bass traps, side and rear surround speakers, and the massive, 4-foot-wide, solid-core entrance door with seals on the sides and top and an auto-drop seal on the bottom.

“Finally, I added a floor-to-ceiling corner broadband bass trap on the left side of the front wall and another along the wall/ceiling boundary. This was also my own design. I’ve now got the modal issues pretty well managed. The IB sub is on the right side, so no bass trap there.”

Speaking of the IB (infinite-baffle) subwoofer, it turned out to be his biggest challenge. “I wanted to do a DIY sub, and after much research, it seemed that an IB sub was truly the best for LFE and clean sound. After looking at the options, I found that I needed to cut through my engineered concrete-foundation wall. I consulted with the engineer who did my load calculations and got his approval to modify the foundation.”


The plan was to install a vertical line array IB subwoofer to the right of the screen. Fortunately, the structural engineer gave thumbs up.

Mike cut a large rectangular hole in the concrete wall to accommodate a baffle plate with four 15″ IB15-8 drivers from Acoustic Elegance in a vertical line array. The backwave from the drivers vents into a utility room that is closed off from the rec room with a sealed door. “I did more isolation with 1-inch styrofoam/sealant at the HVAC duct locations, but I was concerned about the bass booming in the HVAC ducts, since my geothermal system is in the utility room and it has sheet-metal HVAC supply/return main lines entering/exiting the room. If there had been a duct boom, I thought I might add some damping to that area, but it wasn’t necessary.” For more on Mike’s IB sub, check out this thread. Later, he decided to add two more DIY subs in sealed cabinets—one with an 18″ driver and the other with a 15″ driver, both from Stereo Integrity—to help flatten the low-frequency response in the first row; you can read more about that here.

In addition to aural immersion, Mike wanted visual immersion as well. “Initially, I was going to use a 16:9 screen. However, I soon realized that a true home-theater experience required a 2.35:1 ‘scope’ screen. After doing research on AVS Forum in the CIH (constant image height) forum, I decided to build the screen myself.

“There is so much info on AVS Forum about DIY screens, but I found nothing I liked in the way of a scope screen, so I decided to design and build my own. It was fun, especially learning about the proper curvature needed for using an anamorphic lens. The material I chose was Designer White laminate from Home Depot, mainly because I have young kids, so I wanted a robust material that still gives great viewing experience—no hot-spotting, etc.

“The frame is a composite/hybrid metal frame for the structural flat backing with pine board for the curved portion that the DW laminate is attached to. The hardest part was attaching the laminate to the wood. I made a temporary setting jig to guide the laminate onto the frame. My wife helped and we went through three dry runs before applying the contact cement.” For more on Mike’s screen, see his post about it here.


Here, Mike’s DIY curved, 2.35:1 screen is about ready to be mounted on the wall.


Mike outfitted a Sony VPL-VW60 projector with a Panamorph UH380 anamorphic lens; he even designed and built the lens slide! For more on that, see his thread here.

In 2012, the speaker system expanded from 7.1 to 11.1 channels with front wide and height speakers, all from Paradigm. “After that upgrade, AVS Forum member Ed Flower visited me and heard the theater. Listening to various movie clips, he was very impressed with the increased envelopment provided by the wide/height speakers, even knowing those channels were upscaled by DTS Neo:X, not true discrete channels—this was well before Dolby Atmos or Auro. Plus, my front LR speakers are just outside the screen and toed in; along with the side-wall acoustic treatments, Ed thought this produced better imaging than his speakers pointed directly forward behind his acoustically transparent screen. By the end of our visit, he had named my theater ‘The Envelope,’ which I really liked; it never had a name before, and that one was quite fitting.”


Here you can see two of the acoustic panels, equipment rack, and right front main, wide, and height speakers. The IB sub is behind the main speaker covered with grille cloth.

What were Mike’s greatest moments in the process of building his dream theater? “One of the best moments was when I hung the screen and watched in scope for first time; that was very cool! Another was when I fired up the IB sub for Kung Fu Pandaand heard that great ‘ska-doosh!’ at the very end.”


The left wall is treated with several DIY acoustic panels—and some stuffed toys on the secondary sub.

After more than 10 years and about $30,000 of directly related expenses, Mike’s basement home theater is finally finished—or is it? “Every time I’m in there, I’m still giddy at the sound quality, acoustics, and overall sense of immersion. Still, I’m looking forward to late 2016 or 2017, when I’ll tackle the next upgrade to 9.2.8 Dolby Atmos.” Talk about pushing the envelope!


A brightly colored rec room leads to the theater.


Four Berkline motorized recliners comprise the front row, while four Billy Bob manual recliners occupy the second row.

For much more detail about how Mike’s home theater came together, check out the main build thread, which includes links to several related build threads about the sub, screen, acoustic treatments, and other aspects of his theater.

If you’d like your home theater considered for HT of the Month, PM me with the details and a link to your build thread if available.

EQUIPMENT LIST

Sources

Sony PlayStation 3 game console/Blu-ray player
Comcast cable box
Samsung DTB-H260F OTA tuner
Channel Master CM 3020 UHF/VHF/FM antenna
Channel Master CM 7777 Titan2 antenna amplifier

AV Electronics

Denon AVR-4520CI AV receiver
Emotiva XPA-3 power amp (powers front LCR speakers)
Behringer EP2500 power amp (for main IB subwoofer)
Behringer iNuke NU6000DSP power amp (for other two subs)

Processor

Darbee Darblet DVP-5000 video processor

Projector

Sony VPL-VW60
Panamorph UH380 anamorphic lens on DIY slide

Screen

DIY (Designer White laminate surface, 130″ diagonal, 2.35:1, curved, 1.1 gain, non-acoustically transparent)

Speakers

Paradigm Monitor 9 (2, front LR)
Paradigm CC-390 (center)
Paradigm ADP-390 (4, side and rear surround)
Paradigm Mini Monitor bookshelf (4, front wide & height)
DIY IB subwoofer (4 Acoustic Elegance IB15-8 15″ drivers in vertical line array)
DIY subwoofer (1 Stereo Integrity HT18 18″ driver in DIY Sound Group 4-cu-ft sealed enclosure)
DIY subwoofer (1 Stereo Integrity HT15 15″ driver in DIY Sound Group 3-cu-ft sealed enclosure)

Cables

Parts Express speaker cables (14ga/4 for original 7.1, 12ga/2 for wides and heights)
Parts Express HDMI cable for projector (35 feet)

Control

Logitech Harmony 890

Power Conditioning

Panamax M5300-PM power conditioner
Furman PS-Pro II power conditioner/sequencer (subwoofer amps)

Seating

Berkline 12006 powered recliners (4, first row)
Billy Bob manual recliners (4, second row)