Video Walls Archives

All About Digital Canvases

Our articles on digital canvases and video walls provide a comprehensive guide to the emerging category of digital art in the home

ART

your home is your canvas

emerging technology is going beyond just making homes smart to making them expressive

“Everchanging sound and image installations are particularly appealing to those who collect interactive fine art. Modern collections are anything but static. Anyone with a serious NFT collection will attest that they need new ways of displaying artwork. And excitement is just beginning to build around burgeoning artists who work in emerging media, designing original pieces with generative audio and visual elements that constantly change and reflect the dynamic elements of the modern home.” read more

bringing the gallery home

museums and galleries have a lot to teach about the best ways to display digital canvases in home environments

“What is it about looking at fine art that creates a moment of pause instead of merely lulling you into a soporific state? We probably can’t answer that question in this brief piece of writing, but we can address how fine art is typically displayed in galleries. And we can examine how we might make sure these new digital works get the same treatment as the other “static” pieces of art in our homes.” read more

natural wonder

artist Akiko Yamashita discusses the process of translating her large-scale video works from public exhibition to satisfying display at home

“It wasn’t until I encountered Akiko Yamashita’s artwork that I sensed a new kind of intangible spark that leaps from a creation to the person experiencing it. Her large-scale interactive animations, 3D immersions, and light installations invite people to move and create something more entrancing together. The work is interactive in a way that goes beyond technical wizardry. It’s not just cool, it’s more human.” read more

enriching the artist’s digital palette

Barco’s Tim Sinnaeve says artist Akiko Yamashita’s recent comments show that the creative community is beginning to embrace the potential of digital canvases

“Knowing that there are specialized integrators who have established themselves as curators of digital canvases and that there is a mechanism to ensure that the artist’s intentions are honored is something everybody can feel good about. It’s very encouraging to see both artists and collectors starting to pick up on this and to see the increasing enthusiasm for digital canvases in the home.” read more

bringing the gallery home

destinations | artechouse

these tech-meets-art spaces are a must-see (and hear) for anyone eager to experience the leading edge of digital art

“Artechouse is the house that digital art and tech built. If you’ve heard a lot about digital art but have been so far unimpressed by jokey jpgs and trending crypto disasters, try the these New York, Washington, and Miami-based galleries for a really moving view of the newest fine art.” read more

a garden of immersive delights

Ed Gilmore’s midtown Manhattan showroom offers a both thrilling and soothing escape for the senses

“Certain spaces are more memorable because of what they make you forget. That’s how it feels to walk into one of Manhattan’s unforgettable high-end residential-technology hideaways, Gilmore’s Sound Advice. As I stepped into this sensorially refined environment, I forgot my crazy commute and instantly remembered why the showroom is the scene of so much great conversation and innovation.” read more

bringing the gallery home

VIDEO WALLS

video walls go boutique

video walls from the mainstream brands remain a big investment, but that doesn’t mean they’ve worked out all the bugs yet

“LED walls will inevitably shed their training wheels and continue to improve as time goes on—although perhaps not as quickly as other residential video-display technologies. In the meantime, companies like Quantum will attempt to bridge the performance and reliability gaps with highly customized premium offerings like the Cinematic XDR.” read more

great video wall sound is here

an opportunity to audition a center-channel solution in his own home theater showed the author you can have a micro LED wall without compromising the sound

“To have a speaker system that can be optimized without compromise, allowing you to place a pure, strong sonic image exactly where you want it, is going to be a game-changer for creating high-quality sound to go with LED video walls. Given the potential of what I experienced with this system in my own theater, I am looking forward to calibrating the system in the Florida installation next month, which will allow me to take the Movement System from an experimental situation into a real-world home theater environment.” read more

making video walls better

Quantum Media Systems’ Ken Hoffman on what he’s doing to create video walls that live up to the technology’s potential

“It might seem odd to single out one provider of video walls as a luxury-focused solution when the entire category operates in the stratosphere of the high-end entertainment market. But Quantum Media Systems is quickly establishing itself as the go-to provider of video walls that stand out not merely in terms of sheer size but also image quality, reliability, scalability, and—believe it or not—comfort.” read more

great video wall sound—another solution

famed acoustical designer Anthony Grimani offers his unique approach to solving the problem of where to put the center speaker in a video-wall home theater

“The problem of how to design sound systems to support massive LED video walls is one that continues to motivate audio professionals working in the luxury home entertainment space. The fact is this is such a custom domain that it’s hard to imagine a one-size-fits-all panacea that provides optimal sound for every wall in every installation.” read more

million-dollar wall—hundred-dollar sound

video walls have become a big status thing—and an even bigger investment—but getting them to sound good isn’t as easy as you might think

“Video walls can often take up an entire wall but you don’t have the option of putting speakers behind them like you do with a projection screen. SH Acoustics’ Steve Haas has checked out many of the existing audio solutions for LED walls and found them all wanting. But realizing that video walls are quickly becoming the likely future of viewing in premium home entertainment spaces, he’s been more than motivated to try to determine who has the best approach and how it can be optimized.” read more

Great Video Wall Sound–Another Solution

Great Video Wall Sound—Another Solution

Million-Dollar Wall,
Hundred-Dollar Sound

Great Video Wall Sound Is Here

Hidden Treasure

Making Video Walls Better

Famed acoustical designer Anthony Grimani offers his unique approach to solving the problem of where to put the center speaker in a video-wall home theater

by Dennis Burger
February 23, 2023

The problem of how to design sound systems to support massive LED video walls is one that continues to motivate audio professionals working in the luxury home entertainment space. We’ve previously discussed the root of the problem as well as one potential solution, but the fact is this is such a custom domain that it’s hard to imagine a one-size-fits-all panacea that provides optimal sound for every wall in every installation.

I recently spoke with Anthony Grimani, president of Performance Media Industries, Ltd. and co-founder of Grimani Systems, to get his take on how to best design a sound system to accompany a video wall. Before we dug into his patent-pending solution, though, I asked him to reiterate for me why this is a problem to begin with.

“When we’re looking at images on the screen, we want the voices of the characters to come out of the middle of the screen,” he says. “And the way we do that traditionally is we put three speakers behind an acoustically transparent projection screen. But what happens when you replace that acoustically transparent screen with a big, thick screen that won’t let sound through?”

One alternative Grimani has employed is what he refers to as “Phantom+”—essentially using speakers on either side of the screen to create a phantom center speaker where no speaker actually exists. “The typical problem with a phantom center, though,” he says, “is that if your seat is off to one side of the room, the voices move with you. The character in the center of the screen now sounds like they’re coming from the left side of the screen.”

“But we’ve found that by using speakers with really good sound power—like ours, but also ones like Paradigm, KEF, JBL, and a few others companies that go through the effort of distributing the sound nice and wide and constant—that phantom center doesn’t move as hard and as much as with very directional speakers.” Add a bit of EQ to account for the way the listener’s head changes the sound arriving at their ears and this isn’t a bad solution, says Grimani. But it’s not ideal.

Another option—one that doesn’t share the same downsides as the Phantom+ configuration but has its own quirks—is a single speaker above or below the screen. “You might think it would sound like it’s imaging above the characters’ heads, because that’s where the speaker is. And if the speaker has a very focused directivity like a lot of people think you have to have, you’re dominated by the direct sound and you’re going to hear it as up above the image. But because of the wide directivity of our speakers—because what you’re hearing is some direct sound and then a lot of really broad sound-power energy reflecting off the lateral surfaces, there’s enough energy flowing around that it fools your sensation of imaging and you hear the sound centered not above the screen but toward the top third of the screen. You still hear the sound coming from the screen, just higher than perhaps it should.”

Then again, that really only works if there’s room above the screen for a speaker. And given that modular LED video walls are often installed floor-to-ceiling, sometime there simply isn’t room. And that’s where Grimani’s new solution comes in. In short, it works by splitting the sound going to the center channel into two parts: The lower-frequency sounds are sent to the speakers on either side of the screen, whereas the higher frequencies—the ones you can really point to and say “That sound is coming from right there”—are sent to a speaker above the listeners’ heads and aimed at the video wall, so they bounce off and seem to come from close to the middle of the screen.

That’s the simple explanation. For a more in-depth look that explains why and how this all works, we’re going to need to get a bit more technical. What follows is a transcript of my conversation with Grimani about the subject, edit for clarity and brevity.

So, with this two-piece solution, how do you keep the listener from feeling like the sound is coming from two different directions?

The idea is to use a directional waveguide placed generally over your head, and if there’s no spillover of direct sound from the waveguide to your head, you can create the illusion of sound coming directly from the center of the screen. If there’s any amount of direct sound that goes to your head from that overhead speaker, though, you will localize that because it’s the first sound to arrive at your head. It’s only three or four feet away from you. So it’s really important that there not be any leakage.

Now, the waveguide needs to be a pretty good size. Laws of physics are what they are. You can’t cheat that. If we want the crossover point at around 800 Hz, the waveguide is about 12 inches tall. But you can bury that into the rafters in between joists.

With the phantom-center information below 800Hz, you do have to time-align everything really carefully because the path from the speaker to the screen and back to your head is longer than the path coming directly to your head from the left and right speakers. So you have to delay the other speakers so everything arrives at your head at the right time, and that’s all done really easily in the digital domain.

In terms of the overhead speaker, we happen to be using our Conic Section Array waveguide because it works well, but any other waveguide that produces good vertical pattern control with no off-axis lobes and wide-enough coverage works.

Full disclosure: If you sit right in the middle of the room, the image is slightly above the middle of the screen because that speaker bouncing off the screen is creating a mirror image, so it’s sort of like the speaker exists in a mirror-image position behind the screen. If it’s 12 feet from the speaker to the screen, it’s sort of like the sound is coming from 12 feet behind the screen, but in the ceiling. And if you move off-axis, that speaker does move with you a little bit. Imagine having a speaker shooting through an acoustically transparent

Since speakers can’t be placed behind a video wall as they can with a projection screen, the higher-frequency sounds are instead bounced off the screen and back to the listeners.

Anthony Grimani

Anthony Grimani’s solution splits the sound going to the center channel, with the lower frequencies being fed to speakers on either side of the screen and the higher frequencies going to a speaker above the listeners’ heads and aimed at the video wall, so they bounce off and seem to come from close to the middle of the screen

Renderings of the Conic Section Array waveguide, shown with and without a speaker grille. The waveguide is positioned in the ceiling to aim the higher-frequency sounds at the video wall, to then be bounced back to the listening positions in the theater.

screen but instead of right behind the screen, it’s 10 or 12 feet behind the screen. If a speaker is right at the screen, you can move back and forth and the speaker doesn’t appear to move. If the speaker is 10 feet behind the screen and you move off-axis—

There’s a little parallax.

Exactly. So the image of the character speaking onscreen does move with you, but just a little—just to be perfectly clear. I believe in telling the whole story. But I think it’s an acceptable compromise. None of this is as perfect as a speaker behind an acoustically transparent screen. Every alternative has its compromises. It’s about finding the right solution with the fewest compromises. And a lot of times, that’s going to be room-dependent.

Are you installing this solution yet or are you waiting for the patent to be approved?

We have it installed in our demo room. In the world of patents, you have to show you’ve reduced the invention to practice. A patent can be shown to be invalid if the only thing you’ve filed in the patent is an idea you’ve never tested. So don’t patent ideas—patent advancements of the state of the art that you’ve proven to yourself or others works. So we have it working here, and I’m working with an integrator in the Los Angeles area to install it on their big LED wall.

So, you said you’re high-pass filtering the signal going to the ceiling center speaker at 800Hz and sending everything below that to the front speakers. Why 800Hz? That’s not a number I hear people reference when they’re talking about directionality of sound.

Yeah, human hearing has very good localization from about 500 or 600Hz up to about 3kHz. That’s sort of the peak of frequencies you can localize, that you can point at and say, “That sound is coming from right there.”

Below 500Hz, the wavelengths get longer and longer, and your interaural gain—the thing that allows you to localize a sound in 3D space even though we only have two ears—gets fooled because the wavelengths get bigger. You know, a 500Hz wavelength is a little over two feet wide. So, your head is, what, 7 or 8 inches? And when a wave is so much bigger, it’s harder to compare the wavefronts coming from one direction versus another. And as you go down in frequency, it gets harder and harder to point to where a sound is coming from.

In the upper frequencies, a 3kHz signal has a wavelength of just a few inches, maybe half the size of your head, so as you go higher and higher in frequency and the wavelength gets shorter and shorter, the obviousness of correlation between the patterns hitting your left or right ear gets more scrambled because it’s smaller portions of what you’re hearing. And so, above 3kHz or 4kHz, your ability to point toward the source of a sound is also increasingly diminished.

The peak of directionality is from around 500Hz to 3kHz, so if you can take the waveguide down to 500Hz and phantom-image everything else, no problem. But that would be a waveguide that’s much bigger, if you really want good pattern control. It’s just not as practical.

So you go, “What if I try 600? 700? 800?” Somewhere around 800 or 900 is sort of this tipping point where the waveguide is practical and you’re definitely starting to hear more in terms of directionality. That’s not to say it’s the best frequency, it’s just a good compromise between practicality and effectiveness.

We have played with 1000Hz, and if the filters are steep enough and things are controlled enough in the room, you can make it work. And that’s a waveguide that’s about six inches, which is really easy to conceal in a ceiling above the sheetrock in the rafters.

At any rate, if the horn or waveguide is designed correctly, you’re not going to hear any direct energy from straight overhead. Mind you, we’ve seen solutions that involve PA speakers laid on their side, shoved way up close to the screen, and they bounce it off the screen from just a few feet away. That’s just too far forward, because if you look at the specular reflection, that bounce is way too high. It misses the screen most of the time. Also, that speaker playing full-range has a lot of off-axis spill starting at around 1kHz or even a little higher, so you’re hearing the sound directly from that cabinet before you hear the reflection.

I’ve talked to Steve Haas about his experience with such systems. In fact, he wrote an article about it for Cineluxe.

It doesn’t work. It just sounds fuzzy and the dialogue isn’t clear, and it clearly doesn’t sound like it’s coming from the screen, which is the entire point.

Basically, the rule is: With a waveguide or horn—or directional beam-steering array, because that’s also in the patent—there’s a frequency at which you need to roll off and go to a speaker that’s at the front of the screen, otherwise your brain goes, “Oh! I hear it coming from up there.” And you know what? It doesn’t necessarily have to be front left/right phantoms. In the patent, we talk about the fact that it could be just a woofer below the center of the screen, right in the middle. The reason we use the left and rights is because they’re there. Why not use them?

Let’s say you’re doing the sound system in a room for which you’re not the designer and you’re having to work with someone who isn’t willing to budge on aesthetics—what considerations come into play then with a setup like this?

The nice thing about this is that it doesn’t occupy any space at the proscenium. It occupies space somewhere in the ceiling, where we need an acoustically transparent boundary of some sort. And so in the beginning of the design phase, we need to say, “There’s a space up there were we either need a grille or some kind of structure that has fabric and wood and whatever, or a printed fabric that replicates the surrounding materials.” It’s a good way to tackle the aesthetic thing because it’s concealed in the ceiling and functionally invisible. As long as you’ve got the space in the ceiling, it doesn’t have to be a box hanging down like an old projector. In a home theater, more often than not you don’t want a thing hanging up there. That’s ugly.

Bouncing sound off a video wall from a ceiling-mounted speaker creates the impression the sound is originating from a point behind the screen equal to the distance from the speaker to the screen.

“The nice thing about this solution is that it doesn’t occupy any space in a home theater’s proscenium. The waveguide occupies space somewhere in the ceiling instead.”

Dennis Burger is an avid Star Wars scholar, Tolkien fanatic, and Corvette enthusiast who somehow also manages to find time for technological passions including high-end audio, home automation, and video gaming. He lives in the armpit of Alabama with his wife Bethany and their four-legged child Bruno, a 75-pound American Staffordshire Terrier who thinks he’s a Pomeranian.

Making Video Walls Better

making video walls better

“we can create spectacular whites and phenomenally dark blacks simultaneously, so if you’ve downloaded a 4K HDR movie from Kaleidescape, you’ll be getting everything that picture has to deliver”

Quantum Media Systems’ Ken Hoffman on what he’s doing to create video walls that live up to the technology’s potential

by Dennis Burger
January 31, 2023

It may seem odd to single out one provider of LED video walls as a luxury-focused solution when the entire category operates in the stratosphere of the high-end entertainment market. But as we speak with integrators installing these solutions about the pros and cons of such gargantuan screens, one name continues to rise above the buzz surrounding any nascent technology. Quantum Media Systems is quickly establishing itself as the go-to provider of video walls that stand out not merely in terms of sheer size but also image quality, reliability, scalability, and—believe it or not—comfort. What follows is a conversation with company CEO Ken Hoffman, an industry veteran with more than two decades of experience creating world-class private screening rooms, luxury commercial cinemas, post-production facilities, and more, about why Quantum created its Cinematic XDR LED video wall.

Since there are quite a few video wall solutions already, why did you feel it necessary to develop your own? What problems was the XDR system intended to address?

For many years, we worked in digital cinema either building or being part of teams that built screening rooms, post-production facilities, color suites, etc. But we decided around 2014 that we wanted to get back into the residential space and work with integrators, particularly on projects where the clients were approved to be on the Bel Air Circuit. That required Digital Cinema projectors, servers, video processors, etc.

Over the years, we’ve looked at using LED walls as opposed to projection, but the technology just wasn’t there yet. It looked good, but it wasn’t the high-end image quality needed in installations at that level.

So, after more than five years of R&D, we took the plunge about three years ago and decided to see if we could come up with our own approach, and instead of just buying somebody else’s wall and trying to make it better, we became an original equipment manufacturer working directly with component manufacturers. We specify the components—which diodes and integrated circuits to use—and create our own control and processing systems, taking the knowledge about image science we’ve accumulated from years of working at the very high end and from the motion-picture industry and applying that to video walls.

Which problems with the existing technology were you most interested in solving and how successful have you been?

One of the major advantages—aside from purity of color—is light output. Most LED walls will give you 600 or 800 nits, tops, in terms of peak brightness. Our newest wall is rated at 1,200 nits, and that’s calibrated. Uncalibrated, it’s more like 1,600 nits. Once you calibrate it for accurate color, you do lose a little brightness but that still enables us to do HDR better than not only other video walls but than many televisions.

Most HDR content has been created with 1,000 nits as the peak brightness target, and we’re able to provide that and typically more. By doing that, we can produce spectacular whites and phenomenally dark blacks simultaneously, so if you’ve downloaded a 4K HDR movie from Kaleidescape, you’ll be getting everything that picture has to deliver.

Video Walls Go Boutique

also on Cineluxe

Great Video Wall Sound Is Here

Bringing the Gallery Home

Million-Dollar Wall, Hundred-Dollar Sound

Achieving Serenity

Many integrators are concerned about the intense heat coming off video walls from many of the established manufacturers. People have joked that they feel like they’re going to get radiation burns standing in front of those things. Have you done anything to address that?

It is a big problem. That was part of our motivation for making a better wall. We wanted to make our system much more power-efficient. Simply put, if you get better results while using much less power, you generate less heat. We also use other techniques to dissipate heat better.

Nothing kills electronics quicker than excessive heat. Is that a contributing factor to the reports we’re hearing about reliability issues and longevity concerns with other video-wall solutions?

It could be. I agree with you: Heat is always an enemy. So, by generating a lot less heat and dissipating what little heat we do generate, that’s not as much of an issue for us. But in addition, we’re basically theater guys, and we’re helping our integration partners with theaters and media rooms where comfort is a real issue. With many video walls, you need a lot more air conditioning. If your front row is ten feet away and you’re feeling all this heat radiating off the screen, is that really conducive to enjoying a film? That was also a big consideration for us. You can walk right up to our wall and hardly feel any change in temperature.

You mentioned seating distance, which brings up the issue of screen size. What are the theoretical upper limits for the size of your wall?

Functionally, there are no limits. Our LED walls consist of a multitude individual cabinets, and within our cabinets, we have multiple modules. Each cabinet is basically a building block and we install those together to create a screen as large as the client wants, or as large as the room will accommodate.

The only issue is that as you get a lot bigger, the video processing gets a little more involved and you need more processing power, but we have the ability to do very large walls. If someone wanted a 100-foot wall or greater, no problem. It just takes a lot more processing power.

LED video walls are sort of akin to what OLED was ten years ago. Back then, people were paying $25,000 for a 55-inch OLED TV. Their failure rate was super high and the longevity wasn’t great, even on panels that didn’t fail within a year or so. But we’ve come a long way since then. So what would you say to the tech-savvy luxury homeowner who assumes LED video walls are going to follow the same trajectory?

I think there are some similarities but it’s not one-to-one. You can’t just treat this like a large TV. Some companies are trying to move in that direction. By making the installation of their video walls simpler, they’re trying to create economies of scale, so instead of a 100-inch TV, they can sell you a 120- or 130-inch video wall and treat them functionally interchangeably. It works, and the pricing is coming down, but the quality isn’t there. You’re going to see lines in between the modular elements, for example.

Do you mean the lines between each module or the lines between each row of pixels?

If the cabinets and internal modules aren’t aligned correctly you’ll see those lines. And the closer you get to the wall, the more you’ll see them. We’re spending a lot of time during the installation process so that we’re aligning the modules and cabinets optimally. We’re also spending a lot of time in the calibration process.

Would it be fair to say that what you offer is as much a service as a product?

It’s a combination of the two. It’s a much better LED wall, it’s a dramatically better video processing system—it’s a complete package. And then we provide on-site installation and calibration where we spend not just one or two but many days getting everything installed, aligned, integrated, and calibrated. It’s a turnkey solution. We’re focused on the pinnacle of image quality in cinematic environments.

What else might influence a high-end client to decide between a luxury projection system and a QMS Cinematic XDR video wall system?

Since we have a lot of experience with all different brands of projectors, we can explain that projectors can’t provide uniform light across the screen. When we do calibration on projectors, on a typical screen we look at 25 locations, and we get 25 different brightness values. Sometimes the differences are small, sometimes they’re large, but with the LED wall, it’s one value. The screen is 100 percent uniform.

Another consideration is convergence. Many projectors use different chips for red, green, and blue elements of the image, and you have to align those three chips as best you can. Usually, you can get most of the pixels converged but some of them aren’t. In movie theaters, there can be multiple pixels off on convergence. In the home, you’re so close to screen that you can’t be off that much. With LED walls, there are no convergence issues. Each red, green, and blue element lines up perfectly with its mates.

Another issue is that no matter how good your lens is, with a projection system, you can’t have perfect focus over the entire screen. You’re going to lose some focus, especially toward the edges of the screen. So having uniform focus, uniform convergence, and uniform light are major advantages. Add to that the truly deep blacks no projection system can deliver, along with the enhanced brightness no projector can give you, which helps with things like HDR, it’s just a dramatic advantage over projection.

“the truly deep blacks no projection system can deliver along with the enhanced brightness no projector can give you, give our video wall a dramatic advantage over projection”

Great Video Wall Sound Is Here

“Using the TPI controller, I was able to place the sonic image in the exact vertical position where my traditional center speaker
is located”

An opportunity to audition a center-channel solution in his own home theater showed the author you can have a micro LED wall without compromising the sound

by Steve Haas
January 19, 2023

Last June, in “Million-Dollar Wall, Hundred-Dollar Sound,” I talked about how difficult it can be to achieve acceptable sound when using a video wall in a home theater since the front speakers can’t be placed behind the screen as they can when using a projection screen. I mentioned that almost all of the solutions I had encountered resulted in significant compromises but that TPI’s Movement System showed promise, mainly because it includes a controller that uses digital signal processing (DSP) to allow you to adjust the height of the sonic image created by the front speakers.

I recently had a chance to audition the Movement System in my own home theater and was extremely happy with the results. This system uses speakers placed both above and below the video wall to create a phantom sonic image (similar to the horizontal imaging of stereo speakers except done vertically) to match the effect of a traditional center-channel speaker mounted at ear level. And it can accomplish this without the use of additional DSP and without having to employ the services of a professional calibrator (although both are still necessary to achieve optimal performance). Based on my hands-on experience with the TPI system, I have every reason to believe that this solution, along with others based on the same concept, will significantly accelerate the use of video walls in home theaters in place of projection systems.

from theory to reality

I know from my work with solid video screens in museum and commercial environments that effectively placing the sonic image vertically is both achievable and worth the effort. Some people contend that our brains can’t comprehend a vertical image shift as readily as a horizontal one. While there is some truth to that, A/B comparisons of vertical placement show that it can allow the sound of dialogue to be placed where we expect to hear it emanate from when watching a movie or a TV show, which is between half and two-thirds of the way up from the bottom of the screen.

I had been eager to evaluate the TPI system because of its potential to create precise vertical positioning in a home theater environment—particularly since I will soon be calibrating a very large residential project in Florida that uses the Movement speakers.

TPI sent me the two speakers and controller necessary to create a virtual center channel. While I could have requested additional speakers for the left and right front channels as well, I decided to use just the center so I could focus on dialogue. If the system could do dialogue well, I knew it would also be able to handle the left and right positions.

above | Quantum Media Systems‘ Cinematic LED Wall

Million-Dollar Wall, Hundred-Dollar Sound

click on the image to enlarge

TPI’s Movement System uses speakers placed both above and below a video wall for the left, center, and right front positions. A controller is used to adjust the vertical position of the sound coming from each top/bottom pair, to create the same effect as if the speakers had been placed behind the screen.

also on cineluxe

Rooms for Improvement

Video Walls Go Boutique

Achieving Serenity

Bringing the Gallery Home

I set the system up in my home theater, which uses a traditional left-center-right (LCR) speaker array positioned behind an acoustically transparent Stewart projection screen. I then used both objective measurements done with pink noise and subjective listening with program material that contained a lot of dialogue to position the phantom sonic image by way of the controller. I also employed Symetrix DSP to assist with the A/B comparisons of the top/bottom vs. behind-the-screen imaging, as well as with top-only, bottom-only, and top/bottom image comparisons.

Using the TPI controller, I was able to place the sonic image in the exact vertical position where my traditional center speaker is located. I then used the Symetrix DSP to tonally optimize the system so the sound from the top and bottom speakers closely matched that of my existing center speaker, even though they are from two different brands.

What was especially interesting is that the top and bottom pair exhibited a unique fullness of sound that wasn’t due to any type of distortion or phasing but that only added to their presence. Even though I had set the sound from the speakers to arrive at the listening location at exactly the same time, this presence took on an immersive quality because the sound was coming from two different directions, even though it created a solid sonic image in one specific location.

problem solved

The combination of objective measurements and extensive listening has convinced me the top-and-bottom-speaker solution will work. And it has significant advantages over the other existing approaches. By using direct-radiating sound as opposed to reflecting—or bouncing—sound off the video-wall screen, it avoids problems with the reflected sound from the screen becoming mixed with direct sound from the speakers, which creates distortion. Also, having large speakers mounted on the ceiling and aimed at the screen can be both unattractive and distracting. The top-and-bottom approach is especially effective with larger video walls where it can be difficult, if not impossible, to place the center-channel image at an acceptable height using LCR speakers mounted either above or below the screen.

Another advantage is that sound can be optimized for positions in addition to the traditional sweet spot in a theater, which isn’t possible with a single speaker no matter how well it has been calibrated. The type of system considered here would allow for the creation of presets to shift the sweet spot if the homeowners, for instance, wanted to sit in the front row instead of the center row because of the type of programming they were watching.

Also, the shallow height and depth of the Movement speaker cabinets allows them to be easily placed in the relatively small areas available above and below large video walls and allows for flexible placement within those areas. Admittedly, they can’t be used if a client wants an LED screen to fill the whole wall, but doing so would also create basic, non-audio-related problems with things like sight lines. It would be possible, though, to incorporate the speakers into a angled proscenium that would allow them to be positioned forward of the screen, an arrangement that could accommodate any desired screen size.

To have a speaker system that can be optimized without compromise, allowing you to place a pure, strong sonic image exactly where you want it, is going to be a game-changer for creating high-quality sound to go with LED video walls. Given the potential of what I experienced with this system in my own theater, I am looking forward to calibrating the system in the Florida installation next month, which will allow me to take the Movement System from an experimental situation into a real-world home theater environment.

Steve Haas is the Principal Consultant of SH Acoustics, with offices in the NYC & LA areas. Steve has been a leading acoustic and audio design & calibration expert for over 25 years in high-end spaces ranging from home theaters, studios, and live music rooms to major museums and performance venues.

a rendering of TPI’s Movement L center speaker

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