Posted on January 4, 2021 By Diane and Phil Jones
LG GRU510N Laser Projector Review – Special Features:Laser Light Engine, UHD, Smart Wireless Connections
The GRU510N is based on DLP (Digital Light Processing) imaging technology with laser/phosphor illumination. This approach delivers a large vivid image in any space while providing an exceptionally long lifespan.
The light output of the laser light source can be quickly modulated from full power to completely off. A lamp-based system can only dim by 20%, which is not enough to compensate for both dark and bright scenes. This is why Laser projectors usually have a higher dynamic contrast rating than lamp-based units. The GRU510N has a dynamic contrast ratio of 3,000,000:1.
Laser Phosphor illumination combined with sealed DLP optics enables the GRU510N to provide an outstanding performance with exceptional value, durability, and flexibility.
Choosing the GRU510N eliminates routine lamp replacement and maintenance concerns in general. A rated life of 20,000 hours means that five to ten lamp changes can be avoided along with the associated costs
There are three modes to adjust the brightness output of the laser light source. These modes are labeled in reference to their energy savings:
The GRU510N includes UHD resolution by utilizing a 0.47″ DLP chip with XPR technology from TI. While UHD projectors have been available with other imaging technologies, these have often come with increased cost. DLP imagers are widely used for many other reasons, including good uniformity, excellent durability, and color accuracy.
XPR technology leverages the immense speed of the DMD (Digital Micro-mirror Device) to process pixels faster than the rate of the video signal. This speed is how DLP can utilize one imaging chip to create multiple colors as well as multiple pixel locations. In the case of the GRU510N, there are four individual pixels shown on the screen from each of the DMD’s tiny mirrors.
In the earlier DMD designs, the pixel would only pivot on or off using one hinge and axis. The XPR chip tilts in 4 directions and operates fast enough for our eyes to see all the pixels and perceive the entire image all at once.
While the chip only has 2.2 million mirrors, it can deliver a perceived resolution of 8.8 million pixels. This system works so well that it would be difficult for any viewer to notice a difference in resolution compared to a native 4K (8.8 megapixels) imager.
Since the GRU510N is a single-chip DLP projector, you will never have any convergence issues with a 3 chip LCD or LCoS projector, so the image will remain sharp throughout the projector’s life without periodic adjustment.
Also, like all other DLP projectors, the GRU510N has a sealed light path to protect the optics from the dreaded “dust blob.” Having a sealed light path prevents particles of dust from settling inside the light path and obstructing the projected image.
It is truly amazing that it works at all, let alone that it delivers the most durable option possible, with DLP DMDs having an MTBF of 100,000 hours. Another benefit is that DMDs rarely fail and don’t deteriorate in image quality over their lifespan.
While ProBeam projectors like the GRU510N were initially designed for business/education applications, they are equipped with video processors similar to those utilized in LG’s 4K HDR TVs. One benefit of using such a powerful processor is the GRU510N can dynamically tone map HDR content.
The HDR provides a significant improvement in dynamic range as well as color. It lets you see more detail in the shadows and the bright areas and delivers more saturated lifelike colors.
HDR consumer content (4K blu-ray and streaming) is mastered for playback on a flat panel not a projector, so it’s produced at a variety of brightness levels ranging from 1,000 nits (292 fL) to 4,000 (1167fL) nits.
Most 4K HDR-capable projectors can only deliver between 100 nits (29fL) and 200 nits (58 fL). This means no HDR-compatible Home Theater projector can reproduce all the brightness found in consumer HDR content.
HDR projectors utilize tone mapping, which compromises maintaining bright highlight details and delivering full-screen brightness. There is a variety of information embedded in HDR content that an HDR display uses to make picture adjustments. There’s an HDR Infoframe that triggers the projector to switch to the appropriate HDR mode.
When the HDR info frame is detected, most HDR projectors switch to HDR mode with a fixed tone map. It is basically one size fits all, which hurts HDR performance.
Since the MaxFALL/MaxCLL metadata is based on the brightest frame’s average brightness and brightest pixel in the movie, certain scenes with lower than average frame levels can still look way too dark.
Higher-end LCD and OLED TVs have been able to measure the HDR content frame-by-frame to generate accurate metadata dynamically for years. Like LG’s Flat panels, the GRU510N can dynamically measure HDR metadata, which further improves the projector’s HDR performance. The goal is to utilize better the GRU510N’s brightness capabilities based on the content being shown.
The GRU510N includes an optical lens shift adjustment in both horizontal and vertical axes which provides the proper method to adjust the position of the image compared to the installed location. The ability to make this adjustment optically rather than by using digital keystone or other digital geometry correction offers the best possible image.
By using larger lenses than required, the position of the image passing through the lens can be adjusted by moving the lens and image sensor relative to each other inside of the projector. In this case, the adjustments are made by concentric dials on the side each of which allows for the movement of the image on screen, one for vertical and the other for horizontal.
By doing this, you can avoid twisting the projector body towards the screen location if they are slightly misaligned. When a projector is placed so that it is askew to the screen, light from the image does not travel equidistantly to each edge so as it travels farther, the image continues to enlarge. This is what produces trapezoidial images rather than rectangles. If you tilt the projector in two directions, it gets even more complicated. Ideally, the projector can be placed so that its lens is perpendicular to the surface of the screen both horizontally and vertically. In this way the image will be a perfect rectangle as long as the screen is flat.
The process to use lens shift is quite simple – after assuring the image is a perfect rectangle at a smaller than required size, use the lens shift to move the image to the center of the screen horizontally, zoom out, and adjust the height of the image to match the screen height.
In most cases, projectors will allow for an installation location at the top of the image rather than fully centered on the screen. LG provides enough shift to place the projector at the top or bottom of the screen. If a position off center horizontally is required, there is also horizontal shift but the adjustment will always affect the range of shift in the other direction since lenses are circles.
If the position of the projector needs to be outside of the optical shift range, than the excellent capabilities of the built-in 12 point warping will provide further adjustment albeit at the loss of pixels.
Quickly connect the GRU510N to a Bluetooth source for audio playback through the internal or connected audio system as well as the option to connect a Bluetooth audio device.
In today’s world, having Wi-Fi built into devices seems to be the norm. However, this is not common on video projectors, with many offering no option or requiring the use of a USB dongle. Having wireless networking onboard allows for additional flexibility.
While the back panel is equipped with 2 RJ45 connections, (1-ea HDBaseT, LAN) if you are interested in using the MiraCast capability, you will need to connect to the wireless network to wirelessly cast your preferred content
While not a wireless connectivity option, per se, this underlying capability empowers access to content on the web quite easily as well as providing the GUI for accessing media and files for playback from USB. When connected to a robust Wi-Fi network, WebOS browser will provide access to web pages and media from YouTube or Netflix, as examples. Unlike the ThinQ OS, utilized on LGs popular Smart TVs and CineBeam projectors, the projector’s WebOS system does not offer downloadable apps.
While GRU510N has built-in speakers, many consumers will want to connect to a soundbar or AV receiver to take full advantage of the high-quality immersive sound available from many of the projector’s streaming apps. The GRU510N is one of the few projectors on the market equipped with ARC.
If you don’t use ARC or eARC, the only other option would be to connect the optical audio output. Like most TVs/FPJs the optical output cannot pass the latest immersive surround formats to an external sound system, and if you use an optical output, all you are going to provide to your soundbar or receiver is stereo or Dolby Pro Logic information.
HDMI ARC supports multi-channel audio, including Dolby Atmos, but due to bandwidth limitations, it delivers a compressed audio signal, for example Dolby Digital Plus.
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