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Video Wall or Projection: What's Right for You?

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Video Wall or Projection:
What's Right for You?

Tim Adams, February 20, 2019
ProjectorCentral.com

Anyone who has been around the display technology industry knows that LED video walls are hot right now, and one could get the impression that this is becoming the new de facto standard for large format commercial displays in houses of worship, museums, sports bars, retail, and other public settings.

However, just because something is new and high tech doesn't mean it's the best solution. TV video walls (constructed from multiple LCD panels) and that old standby, projection, still compete against LED walls. So if you're in the market for a large format display that goes beyond traditional flat-panel sizes, it is important to understand the key factors that make one solution better than another for a given space. To help understand these variables, we'll look at all three of these options.

LED Video Walls

Leyard-Planar-video-wall-2
LED video walls offer long life, high brightness, and even high resolution as demonstrated by this Leyard 8K display shown by Planar at the 2016 NAB Show. Its TWA series tiles use a 1.2 mm pixel pitch.

Even taking into account its higher initial cost, it might seem to the casual observer that the LED video wall option presents the best value. Colors are vibrant and vivid, and unlike other displays they can be used in direct sunlight. Most critically for the long-term cost equation, lifespan can run between 50,000 hours and even upwards of 200,000 hours given that most users do not run their walls at full brightness.

But there are other aspects to consider. Let's start with the variable of resolution and how that can affect cost. While projectors and panel displays have an inherent pixel count that establishes their ability to reproduce detail, LED video walls use something called "pixel pitch" to establish the image resolution at a minimum viewing distance. The smaller the pixel pitch, measured in millimeters from the center of one pixel to the center of an adjoining pixel, the better the image. A smaller pixel pitch means more LEDs are packed into a square inch, which increases pixel density and thus means the image looks complete and seamless from a closer viewing distance.

The LED tiles used to build a video wall are available with a pixel pitch ranging from less than 1 mm to as much as 10 mm. For a viewing distance at around 12 feet, you will need a 1 mm pixel pitch or below. The rough formula (assuming viewers with natural or corrected 20/20 vision) is to take a pixel pitch and multiply by 10 to arrive at a close approximation of the correct minimum viewing distance in feet. Planar, a prominent visual display manufacturer, provides a helpful table for different pixel pitches and their respective viewing distances.

Naturally, a tighter pixel pitch carries a higher premium. So the bottom line here is that the need for sharp images at relatively close viewing distances can dramatically and quickly drive up your cost.

NEC-LED-tile-front-back
LED tiles, such as the NEC dvLED module pictured here, are available in various pixel pitches and dimensions.

Another factor to consider is that LEDs are made in batches, and thus it is extremely important to ensure that the LED video wall manufacturer is guaranteeing that the LED "tiles" making up your wall are all from the same batch of LEDs; this is to ensure color accuracy and continuity from tile to tile. It might seem odd that LEDs from different batches, even from the same manufacturer, can vary quite widely in color reproduction and consistency. But the nature of how LEDs are made and how they create color, differences in phosphor coatings, and their inherent color drift and LED degradation over time make it absolutely critical to have LED video tiles with LEDs from the same batch. This insures that your degradation and color drift is consistent across your entire display.

Many of the more reputable video wall manufacturers and/or resellers will include extra tiles in an order as spares to help with this color drift and degradation when tiles need to be serviced or repaired. However, another issue arises with this practice. If you have been using your video wall for a couple of years and a video tile fails or needs servicing (it does happen), your spare tile is now brand new, but the rest of your video wall has been experiencing color drift and degradation for those two years. You now have the potential for brightness and/or color inconsistency issues that can be painstaking and time-consuming to rectify.

Okay, so you may still be thinking at this point that these are fairly minor issues compared to the overwhelming benefits the LED video wall provides. However, we are not done yet. Manufacturers of less expensive video walls do not always provide adequate shielding for their products and thus these video walls can emit powerful RF energy, wreaking havoc on wireless microphone, in-ear monitor (IEM), video, intercom and even wireless networking equipment in the vicinity. This can be a problem for houses of worship or performance venues. The consequences of purchasing a value-priced LED video wall solution may not necessarily be financial or tangible, but can be equally as frustrating and/or painful.

Additionally, the structure requirements for supporting these walls can be quite significant, and not all manufacturers provide the capability of servicing their tiles from the front, meaning that you may have to create access to the area behind the wall before you install the system. You also have the power requirements, usually measured in kilowatts, to power all of those LED tiles. This means the costs to operate the wall can add a potentially significant amount to your monthly power bill.

Finally, the likelihood that you will need to also sign a service contract with your system integrator can add even more cost to these systems. These are secondary and ancillary costs to the cost of the product, installation, and configuration and can represent a significant set of what some would consider "hidden costs" to an upgrade project.

In terms of costs, video walls can vary quite widely based on manufacturer, pixel pitch, the LED technology used in the tiles, and whether you are buying direct from the manufacturer or going through a reseller. It is not unheard of to quickly approach the $100,000 mark for a quality LED video wall solution, so properly prepare yourself if you are wanting to seek out bids and proposals. When all of the caveats are factored into the true, total cost of ownership, LED video walls usually only pencil out financially for well-funded corporate entities or perhaps larger houses of worship that have several thousand or tens of thousands of members to financially support not only the initial outlay of funds for an LED video wall, but also the ongoing costs for service and other issues that arise.

With all of that said, I know I need to take a moment and address those situations where high ambient lighting, especially direct sunlight, make a projection solution, and even LCD video walls, either unsuitable or undesirable. In these extreme situations, the only viable option would be a direct-view LED video wall because it is the only solution that can overcome those lighting conditions and provide a solid and acceptable image in terms of both brightness and color rendition. But beyond these conditions, there are other and probably more cost-effective options to consider.

LCD Video Walls

NASA-Hyperwall-LCD-Videowall
LCD video walls, such as NASA's Hyperwall display that shows sea surface temperatures, have a visible grid between the separate LCD panels, but are more cost-effective than LED walls.

The second solution we are going to look at involves a grid of commercial panel displays, often mistaken for TVs, that is arranged on a supporting structure and shows one image across the displays.

Although somewhat similar in approach to LED video walls in that multiple smaller displays are used to recreate a single image, LCD video walls made from traditional panel displays do have some differences. First is that the delineation between displays is much more noticeable due to the bezels that mark the edges of each panel. We have been seeing smaller and smaller bezels being introduced in recent years, some as thin as 1 mm, but that line is something that cannot truly be done away with at this time.

Viewers do get accustomed to this grid interrupting the image if given enough time to sit and view content, but for some end users, this is enough to cause them to look at other solutions.

As with LED video walls, you still have multiple displays that can degrade and color drift over time at different rates. But unlike the LED video walls, sometimes your multiple displays can have color and brightness inconsistency straight out of the box. These inconsistencies can usually be dealt with through the system processor/controller, but this takes time, which can increase your installation costs, and thus the overall costs for the project itself.

Also, unlike the LED video wall solution, I have never seen an integrator or manufacturer provide spare panel units for an LCD video wall. This means that if a display dies or falls out of color/brightness consistency with the other units and can't be corrected via the controller, there will be gaping hole in the wall until that unit is either repaired or replaced. You can purchase spare units at the time of initial purchase, but you again have the color/brightness consistency issue to deal with during installation of the new part, not to mention additional cost.

Another difference is that because the LCD displays are based on standard TV diagonal sizes they are not as flexible in their configuration as an LED video wall, whose tiles are often square or rectangular, but smaller in physical measurements. This means that ultra-wide, ultra-tall, or custom shapes are much easier to create, whereas your LCD displays, typically built to a 16:9 aspect ratio, will always leave you with large, rectangular building blocks.

From a cost perspective, LCD video walls are often significantly less expensive than their LED video wall competition. However, you have to take into account the drawbacks listed above and whether those outweigh the additional cost and benefits of LED video walls.

Projection

MountainViewChurch-wLargeScreens
With properly selected screen size and materials, and appropriate lumen output, modern projectors can be an effective alternative to large-scale direct-view displays.

Projection today remains a very viable and capable technology for large-scale displays in virtually all environments other than direct sunlight, and out of the three solutions we are looking at here, it is easily the least expensive from both a cost-per-inch standpoint in the initial purchase and when diving into total cost of ownership. This value proposition makes it particularly attractive for the small-to-midsize churches that constitute the majority of clientele at our custom audio/video integration company.

You can point to some recent advances in projection technology for this current state of affairs. In particular, laser light sources in projectors make long-term care and operation more cost-effective than ever. Most laser projectors will offer at least a 20,000 hour lifespan—eliminating the requirement for ongoing lamp replacements—along with minimal filter maintenance, and they come in all categories of brightness and budgets.

You don't have to sacrifice on resolution, either, as most laser projectors for commercial applications are either 1080p (1920x1080) or WUXGA (1920x1200) natively. More affordable high output 4K or UHD laser models are also becoming available now, which may prove helpful for house-of-worship, sports bar, museum, or other installations where some viewers are at close proximity to the screen.

This brings us to the topic of screen material. It might take you by surprise if you're new to projection, but yes, the screen material you choose can have a significant impact on the quality of your final image. Of course, control over your ambient lighting is important, but there are now viable and reasonably priced options available if you want to be able to leave your lights on during a worship service and still have a great image that legibly displays text, graphics or moving video for everyone in the audience.

ALR-Screen-Demo
Ambient-light-rejecting screen materials, as demonstrated here in the bottom sample, allow projection to combat bright conditions.

Options for screens you evaluate should always include the latest ambient-light rejecting (ALR) screen materials. These are often a tad more expensive than a simple matte white screen, but the benefits of having your screen actively working to improve the contrast of your projected image can take your experience from just-okay to amazing. It is important to note here that most of the bad experiences I have heard in regards to projection have to do with one of these two scenarios: either the projector was not bright enough for the use case, and/or the projector and screen material were not properly matched. By investigating all of your projector and screen options, and calling in a professional for guidance if needed, you're assured of getting the result you want and the most cost-effective use of your budget.

Conclusion

Finding the right solution for your own space requires taking into account the benefits vs. drawbacks of any technology, the total cost of ownership and how that fits your budget, and ease-of-use. Often, the process starts with analyzing how you'll use the display and assessing your environment to determine appropriate image size and any lighting challenges you might need to overcome. I expect to cover these topics in the future. But in the meantime, this article has hopefully raised your awareness of some basic differences among today's top large-scale display options. There's never been a more exciting time for display technology, but it's important to know what constitutes the best value for your particular situation.

Tim Adams is president and chief systems designer for Timato Systems, an audio/video integration company specializing in servicing the sound, lighting, video, projection and live-streaming needs of churches and other houses of worship. He can be reached at info@timatosystems.com.

(03/22/19 - 11:25 AM PST)
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