Home Theater Geeks 530: DIY to the Nth Degree

Summary

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Home Theater Geeks 530: DIY to the Nth Degree

Date: May 7, 2026 | Host: Scott Wilkinson (TWiT)
Episode Theme:
A deep dive into the ultimate DIY home theater project by Norwegian enthusiast Bjorn Eric Forberg, highlighting extreme craftsmanship, unconventional design decisions, and relentless personal effort in building a “room within a room” theater—including DIY speakers, acoustics, and unique solutions for performance and aesthetics.

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Episode Overview

Scott Wilkinson revisits one of his all-time favorite home theater builds, originally featured on AVS Forum in 2014: the astonishing, wholly DIY project of Bjorn Eric Forberg from Oslo, Norway. Bjorn didn’t just assemble a system—he designed and hand-built the speakers, acoustic treatments, and even created a fully isolated theater structure within his basement. The episode explores the thinking, the challenges, and the innovative techniques that mark this theater as a passion-fueled labor of love.

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Key Discussion Points & Insights

1. Room-Within-a-Room Construction and Sound Isolation

• [01:32] Scott introduces the build: Bjorn constructed his theater in “a long narrow basement,” dividing the space so “the other half was going to be his workshop where he built everything from scratch.”
• Isolation priority: “Bjorn built a room within a room for maximum sound isolation. He really wanted to be able to crank it up and to not bother other people in the house.” (Scott, 02:15)
• Technical details: Double-layer plasterboard with green glue between layers; air gap at the doorway, “so there is significant sound isolation between this room and the rest of the house.”

2. Speaker Design – DIY to Extremes

• [03:14] All speakers and subwoofers were custom-built.
• Front LCRs: Based on a Stig Erik Tongan design, but with Bjorn’s modifications—3 Bama 15” woofers (25-200 Hz), TAD 12” midrange (175-2000 Hz), and Bama horn tweeter (2200-21,000 Hz).
  • “All the surround channels are based on the same principle… They all have the same sonic signature as the front speakers, which is great in my opinion.” (Scott, 04:16)
• Subwoofers: Custom Bama 18” drivers extending to 13 Hz, “only used for LFE—low frequency extension.”
• Full-range approach: “All the main channels are set to large speakers, so the speakers themselves can reproduce full range… Not many can.” (Scott, 05:25)

Quote: “You could not hear the sound cross between the mains and the subs.” (Recalling Bjorn’s words, 05:02)

3. Acoustic Treatments & Diffuser Design

• [06:01] Bjorn used ‘Acoustic Calculator’ software to target ceiling and back wall reflections.
• Handbuilt diffusers: “2 by 2 inch lumber cut into different lengths to build a bunch of diffuser panels.”
• Ceiling & back wall: Special elongated ceiling diffusers and modified low-frequency diffusers for the back wall, “to extend frequency diffusion down to 200 hertz.”
• Minimal absorption: Only at first reflection points, for a “very natural and open sound.” (Scott, 07:39)

Quote: “He says the frequency response of the room is flat down to 13 Hz and up to 21 kHz, but he adjusted it to add a bit more weight to the LFE, those really low frequency rumbles, for greater effect on movies...” (Scott, 08:04)

4. Instrumentation and Gear Choices

• [13:00] Projection Screen:
  • “He tried 10 different screens, he says, and finally found one that does not destroy the sound and gives a good picture at the same time.”
  • Settled on a 138-inch wide 2.35:1 acoustically transparent woven screen from Norwegian company DreamScreen, with a custom hinged frame for easy access.
• Seating:
  • Front row: DreamScreen Cineseat Promoter; Rear: DreamScreen Theater model.
• Electronics:
  • Amplification: Crown Itech amps.
  • Processing: Active crossover & DSP, Sherbourn PT730 surround, Oppo BDP-95 & 103 Blu-ray players, Monster cables.
  • Physical isolation: All equipment outside the theater, IR repeaters for control.
• Projector: Sony VPL VW55ES.

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Notable Quotes & Memorable Moments

• On DIY philosophy:
  “This is DIY to the nth degree… He built the speakers and the acoustic diffusers in the room.” (Scott, 01:34)
• On system performance:
  “The sensitivity of these speakers is remarkable. 103 decibels per watt per meter for the front LCRS, 101 for the surrounds, and 100 for the subs… He’s measured the main speakers at 134 dB SPL, which is way louder than I would ever want to listen to this system.” (Scott, 06:03)
• Cost contrast:
  “The total cost of the room, he reports, was no more than about $8,000. But the gear was another story. Bjorn estimates that the total equipment cost was maybe around $140,000. As he explained, the VAT… is 25% in Norway, so everything costs more there.” (Scott, 15:20)
• On heartbreak:
  “Unfortunately, Bjorn has since moved from this house and he couldn’t bring the theater with him… he actually tore down the theater. So unlike many home theater owners, he didn’t have the opportunity to upgrade that beautiful system…” (Scott, 16:20)
• Encouragement to listeners:
  “I hope it serves as an inspiration for others to dig into their hobby, their home theater hobby as DIYers, because it’s well worth it.” (Scott, 17:10)

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Timeline of Key Segments

| Timestamp | Segment | |-----------|--------------------------------------------------------------------------------------------------| | 01:32 | Episode theme intro & project overview | | 02:00 | Room-within-a-room and isolation construction | | 03:14 | Speaker build process and design philosophy | | 06:01 | Custom acoustics and diffuser solutions | | 08:00 | Subwoofer integration and unique full-range approach | | 13:00 | Projection screen challenge and innovative solution | | 14:10 | Equipment rack & outboard electronics | | 15:20 | Cost breakdown and financial realities of a “no-compromise” DIY build | | 16:20 | The bittersweet end: tearing down the theater after moving | | 17:10 | Closing thoughts, inspiration for DIYers, and listener call-to-action |

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Final Thoughts & Takeaways

• Dedication and Ingenuity: Bjorn’s project stands as one of the purest testaments to the depth and possibility of the DIY home theater hobby. Building not just components, but acoustic treatments and even the room itself from scratch, he showcases a holistic, hands-on approach that prioritizes both technical excellence and personal satisfaction.
• Unconventional Solutions: The decision to keep all speakers ‘large’ and use subs only for LFE, as well as custom diffusers and a hinged screen, demonstrate creative problem-solving and a willingness to question orthodox approaches.
• Inspiration for the Community: Despite the eventual dismantling of the theater, Bjorn’s extraordinary effort is a rallying point for DIYers worldwide—showing what’s possible with vision, patience, and skill.

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For More:

• Check the show notes for a link to Bjorn’s original AVS Forum thread, including construction photos and further discussion.
• If you have a proud DIY theater or questions for Scott, contact him at [e-mail]—you might even be featured on a future episode.

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“Geek out." — Scott Wilkinson, [17:35]

Transcript

[A]

In this episode of Home Theater Geeks, I profile a home theater by an owner who takes DIY to the next level. So stick around.

[B]

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[A]

Hey there, Scott Wilkinson here, the home theater geek. In this episode, I'm going to profile a home theater that I originally profiled on AVS Forum. Way back in 2014. The Home Theater was built by Bjorn Eric Forberg, Norwegian, who built this theater in his home near Oslo, Norway. Now, not only did he build the theater itself, he built the speakers and the acoustic diffusers in the room. This is DIY to the nth degree. Now, the theater is built in a long narrow basement, in half of it, I should say. And the other half was going to be his workshop where he built everything from scratch. So here you can see these, this long narrow basement. And he built basically a room within a room. You can see in this plan drawing, which he created. Look at this as if the central section is sort of the view from above and the four side sections are the walls. Imagine that if you had a box, an open box, and you folded down the sides of the box, that's what this would be. So those four side panels are the side walls. And you can see there that you can see the speakers in the front wall. You can see the absorbers are in yellow, the diffusers are in green, you can see the seats there, and so on. So it's a very nice way to do a floor plan, or rather a plan drawing, I should say, because it's not only the floor, it's also the walls in two dimensions. It's it's pretty cool. So Bjorn built a room within a room for maximum sound isolation. He really wanted to be able to crank it up and to not bother other people in the house. So the next graphic we can show you is the the drywall, the room within the room. And you can see that the walls are double layer plasterboard with green glue in between the layers. And you can see there in the doorway that there's actually an air gap as well. So there is significant sound isolation between this room and the rest of the house. Now in the next graph we can see one of the speakers being built, and that is based on a design by a fellow by the name of Stig Eric Tongan. But Bjorn modified the design as he put it. The LCRs include three Bama 15 inch woofers to reproduce the range from 25 to 200 Hertz, a tad 12 inch mid range to cover 175 to 2000 Hertz, and a Bama horn tweeter that goes from 2200 up to 21000 Hertz or 21 kilohertz. All the surround channels are based on the same principle with a Bama 15 inch woofer covering 25 all the way to 900Hz and a Bama horn tweeter from 900 to 21Khz. They all have the same sonic signature as the front speakers, which is great in my opinion. Now, the subwoofers were designed to blend well with the main speakers. And these of course were also built by Bjorn. He used Bama 18 inch drivers that extend down to 13 Hertz. And as he he wrote, when I tested the system, there were only level adjustments that were needed. I did not. You could not hear the sound cross between the mains and the subs. Also, he said the subs are only used for LFE low frequency extension. All the main channels are set to large speakers, so the speakers themselves can reproduce full range. They're not crossed over as in most home theaters. And those large speakers can play from 28Hz all the way up to 20Khz and a little beyond. So, you know, he's not following the traditional wisdom, shall we say, of crossing over the main speakers to the subwoofer so that all channels get reproduced by the subwoofer, the low frequencies, but only the LFE channel gets reproduced by the subwoofers. So an interesting approach and his system can certainly handle it. Not many can. So here's a great picture of the in an intermediate stage of Development. Here's Bjorn sitting atop the center speaker to give a sense of the scale of that whole front center, that whole front system there. It's really remarkable. It's quite big. And here in this picture, we can see the complete front speaker setup which fills the entire wall behind what will be the screen. The sensitivity of these speakers is remarkable. 103 decibels per watt per meter for the front LCRS, 101 decibels for the surrounds, and 100 decibels for the subs. He says he's measured the main speakers at 134 DB SPL, which is way louder than I would ever want to listen to this system. But it's one reason why he really wanted to build a room within a room that isolates from the rest of the house. So Bjorn used a program called Acoustic Calculator to determine that the most problematic frequencies in terms of reflection from the ceiling anyway, extended from about 750 to 3500Hz. And the areas that would create the most problems were down in the middle and near the walls. So he used 2 by 2 inch lumber cut into different lengths to build a bunch of diffuser panels, which we can see in the next graphic. These are com. This is a common design for diffuser panels. And he built some that were very long to place along the ceiling, which he said was one of the big problems of concern. And he also built some for the back wall, which we can see in the next graphic. In the back wall, he wanted to extend the frequency diffusion down to 200 hertz. So he modified his diffuser design a bit and covered the back wall with these panels after all the treatments were installed on the ceiling and the back wall. Bjorn says the sound is very natural and open, which I wouldn't doubt. He's not using a lot of absorption except at the first reflection points on the sidewalls. So he's getting. I think I agree with. He must be getting a very natural and open sound. And he says the frequency response of the room is flat down to 13Hz and up to 21Khz. But he says he adjusted, adjusted it to add a bit more weight to the lfe, those really low frequency rumbles, for greater effect on movies, as he said. You can see in this picture that the two DIY 18 inch subwoofers are in the lower corners. And all of this, the speakers and the diffusers were subsequently covered with acoustically transparent fabric.

[B]

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[A]

So Bjorn talked about the projection screen. And he said he had a real challenge picking a good one. He tried 10 different screens, he says, and finally found one that does not destroy the sound and gives a good picture at the same time. It's 138 inch wide, 2.35 to 1, acoustically transparent woven screen from a Norwegian company called Dream Screen. And he built the frame for the screen with a hinge at the top so it could be lifted out of the way to access the speakers behind it. Good idea. I like that idea a lot. The seats, which you can see in here in the next picture a little better, are also from the company Dream Screen. The front three are the Cineseat promoter and the rear three are the theater model. So they look mighty nice to me. Now in the next graphic we can see some of the equipment that he is using. He's using Crown Itech amplifiers to provide all power to all those speakers, an active crossover, and DSP. The surround processor is a shareborn PT730. Remember this is from 2014 and two Blu Ray players, the Oppo BDP95 and 103 monster cables throughout. And all these electronics that you see here are located outside the theater and controlled by IR repeaters. So let's take one final look at this wonderful theater. It's a really beautiful job, if you ask me. I love that cloth on the, on the walls there with that swirly curvy pattern, all in blacks and grays. Beautiful, just beautiful. The projector, by the way, is the Sony VPL VW55ES. Now, as, as I mentioned before, he built everything himself. And as a result, the total cost of the room, he reports, was no more than about $8,000. But the gear was another story. Bjorn estimates that the total equipment cost was maybe around $140,000. As he. As he explained, the VAT or value added tax is 25% in Norway, so everything costs more there. And. Okay, I can I get that. But I have no doubt it's worth every penny. I really think it. It's beautiful. Now we're going to put in the show notes, a link to the build thread that Bjorn put up for his theater and he joined in 2012 and he started this thread in 2012 as well. I I featured the theater in 2014 and if you were paying attention to the equipment, you probably noticed that the system is only high definition, not ultra HD or 4K. And it's 7.1 audio. There's no Atmos. Unfortunately, Bjorn has since moved from this house and he couldn't bring the theater with him. According to his build thread, if you go to the last page you will see a heartbreaking sight. He actually tore down the theater. So unlike many home theater owners, he didn't have the opportunity to upgrade that Beautiful system to 4K Atmos High Dynamic range. I really wish he had been able to do that. But even without those enhancements, I'm sure that this theater was exceptional, spectacular in every way, and I hope it serves as an inspiration for others to dig into their hobby, their home theater hobby as DIYers, because it's well worth it. If you have a question for me, send it on along to HTGWIT TV and I'll answer as many as I can right here on the show. And if you have a home theater you're proud of, send me some pics. I'd love to see them and maybe we'll get you on the show to talk about it. Until next time, geek out.

[C]

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