LG HU710PW Real 4k Laser Hybrid Projector Review: World Class Picture Quality Just Got More Affordable

Last year, LG introduced the HU810PW, its first laser projector that did away with the traditional color wheel and directly mated two laser light sources to a DLP chip. At 2700 lumens, it was almost certainly a "bright" projector and more suited for large screen sizes. The HU710PW is the more home-theater-oriented spiritual successor to the HU810PW and makes several changes to LG's award-winning HU810PW. This smaller new projector does away with the second laser source and instead opts for two additional LED diodes that will allow for great color separation across all three channels. It will produce 100% color lumens at a lumen output of 2000 lux - which is the ideal standard for home theater projectors.  It carries a price tag of $2499 and boasts an amazing lamp life of 20,000 hours.

Introduction and specifications

The LG HU710PW gets full HDMI 2.1 support with eARC (32 channels of audio, 24 bit, 192 KHz, Atmos support). The projector supports 12 bit color on YCBCR 4:2:2 (the native format for Blu-rays and most television content) and 10 bit color for RGB 4:4:4. It features a stunning DCI P3 94% color gamut (this number is smaller than the LG HU810PW but is actually misleading as I will mention in the review later) and features an impressive native ANSI contrast ratio thanks to its laser engine. All in all, it punches far above its weight class based on the on-paper specifications so let's see how it performs in real life.

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While most DLP projectors (the vast majority of projectors in the mainstream segment) have a light source that lasts, at most, 4000 hours, LG is using a laser light source coupled with 2x LED light sources that will last for at least 20,000 hours. Now let's talk about major technical changes from the HU810PW. The HU810PW system worked by having two laser light sources: Red and Blue. The blue laser was passed through a dichroic wheel (which alternates the laser to the green or blue channel) and eventually static phosphor (which is a green refiner that LG calls G-Rap) to produce the green channel.

The use of the dichroic wheel meant that the HU810PW did not have completely discrete channels for the different colors. The inclusion of a color wheel also slightly increased the Rainbow Effect in a system where there should have been none. With the HU710PW, the dichroic color wheel is gone and each color channel has its own dedicated light source as you can see below.

The result? virtually all of the lumens here (in theory) are color lumens. The difference between white lumens and color lumens is a very important one when it comes to judging color quality. You can crank DLP projectors up to fairly high lumens, but since they have a white light source passing through a color wheel  (which is just a combination of color filters) you find out that colored lumens are a fraction of the total lumens. It also mostly eliminates any rainbow effect (which is prevalent in color wheel systems). That said, if you are watching a very very high contrast scene (think black and white movies) and you try really hard - you *can* still see some RBE although I can confidently say that this is the lowest RBE has ever been in DLP projectors.

The projector is powered by a Texas Instruments 0.47" DMD XPR chip. For the uninitiated, the XPR chip is able to offer true 4k resolution with the true resolving power of 4k pixel grids or 8.3 million pixels on-screen. This is different from PRO-UHD/4k-enhanced variants of XPR which cannot project a true 4K image (up to 4.15 million pixels). It sort of works like how CRTs of old used to function (with progressive lines being scanned on the monitor and your brain making them into a single image). Just so I am absolutely clear about this, this is real 4K, unlike 4K enhanced/PRO-UHD projectors which project a sharpened 1440p native image without actually projecting 2160p pixels.

The light border from the HU810PW is still present but greatly reduced. This is not really an issue if your projected image fits your screen (as you can simply zoom in the image till the light border vanishes into the screen border) but could be an issue if you plan to project on a bare wall or a screen that does not have dark borders. It also means that the actual throw distance will be slightly longer than advertised as you will have to zoom in more to get rid of the borders.

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The laser system used by LG is from NICHIA Corp. which comes with laser-based adaptive contrast. This is tech that analyses every frame being projected and dynamically adjusts the laser output for incredible contrast ratios. The adaptive contrast is a far more reactive and able to preserve color calibration more than the older HU810PW.

In fact, with all "dynamic" features turned on, the LG HU710PW is capable of achieving a dynamic FOFO contrast ratio of 2 million to 1. The same tech applied to HDR turns into dynamic tone mapping where every frame is analyzed for optimal light output. Frame by frame analysis is a feature that is usually not present in projectors in this price range and reserved for expensive projectors like the JVC NX5 or NX7 (which are more than twice the cost of the LG).

If that wasn't enough LG has another trick up their sleeve: controllable iris. Combined with their 100% color lumen projection engine, a fully controllable iris allows you to actually adjust the light output of the projector in a usable manner. This is something that would not have been possible if this was a color wheel-based projector as increasing or decreasing the iris would wash out colors (as white lumens would go up more than color lumens). The controllable iris allows this projector to go from a vivid TV-like, bright projector to a decent cinema projector with good blacks. Note however that while this is a controllable iris - it is not a dynamic iris - which automatically adjusts according to the input frame.

Calibrating the LG HU710PW 4k laser projector

The LG HU710PW is not factory calibrated but we were pleased to see that out-of-box calibration is much much better than the HU810PW which had a very large green tint. The HU710PW also has a  green and blue tint but is significantly improved over the HU810PW and easy to calibrate away.

Like the HU810PW, the HU710PW has the highest color depth when the iris is wide open and will quickly show increasing strengths of green tints as the iris is closed. Unlike the HU810PW however, which was not usable in dark rooms with the iris wide open (due to vastly faded blacks), the HU710PW is actually perfectly usable even with the Iris wide open. With the Iris wide open, we measured black levels improving from 0.36 lux (HU810PW) to 0.12 lux (HU710PW) - which takes them from being unusable on a 150-inch screen to acceptable.

With the LG HU710PW, there was a general consensus that the highest wow factor was attained with the iris wide open and not from a black-level optimizing calibration. This allows us to present jaw-dropping highlight performance with acceptable black levels. The alternative (for purists) is pitch black levels and dim highlights (with the iris closed). In that case, we would advise using a gain screen to bring out some of the highlights.

Most visually pleasing calibration (with excellent highlights and acceptable blacks):

• Mode: Standard (SDR)
• Contrast: 95
• Iris Mode: Bright Room
• Adaptive Contrast: High
• White Balance (2-point): High: -17 Green, -5 Blue, Low: -15 Green, -4 Blue
• Color Temperature: Warm
• Fine Tune, Color Upgrade: Medium
• Sharpness: 10
• Smooth Gradation: Low
• Gamma 1.9 (and then calibrated at source to offset black level difference)

We also noted that the projector ends up crushing shadow details if any gamma level other than 1.9 is used. In other words, we would not advise using Gamma 2.2, 2.4, or BT gamma settings and sticking with 1.9 and calibrating the gamma from the source. We used a 30% gamma increase in our video source (NVIDIA control panel) to bring the total gamma of the projected back to 2.4.

Please note that this is not the setting with the deepest blacks - but is the one that looks the most pleasing to the eye and will be sure to blow away audiences. For deeper blacks (at the cost of significantly reduced highlight performance), we recommend an iris value of 5 but that will require re-calibrating as the green tint will increase and also require a gain screen at 150 inches.

The LG HU710PW have one of the best image positioning systems we have seen. It features both horizontal and vertical lens shift with an absolute ton of flexibility. On our 150 inch projection, the entire image could be moved 50% in any of the 4 directions. Combined with the screw legs, this LG will be an easy setup in any home theater.

Calibrated performance

All testing was done on a 150 inch matte white gain 1.0 screen in a completely light-controlled room.

The HU710PW retains a lot of the versatility of its older brother. With the Iris full open, you get access to world-class highlights with acceptable blacks (our preferred mode of use), and with the touch of a button, you can get soul-crushing blacks with middling highlight performance. There is so much flexibility in this offering from LG that we have been testing this guy for a little over 1 month and *still* are not sure if we have the most optimal configuration down pat.

The LG HU710PW in calibrated cinema mode features an incredible native contrast ratio of 2500:1 on a 150-inch image. The reason why LG can achieve this level of contrast is of course due to the fact that it has a laser-based engine. To put this into context, a lot of 1080p monitors ship with a native contrast ratio of 1000:1. At source, the native contrast ratio (in cinema calibrated mode) was around 39750:1. This is once again - a very impressive number.

At 150 inch, the only usable iris values are 4 through 10 (5 to 11 on the chart) since anything below 4 will compromise highlights too much. In this range, LG is capable of expressing the most perceived dynamic range with the Iris wide open. Once calibrated, we felt that adaptive contrast handled day and night scenes much better than the HU810PW as well.

An iris level of 0 provides the deepest blacks we have ever seen (0.005 lux!)  and dark scenes are incredible to look at but unless you are using a much smaller screen size (think 100 inch) with a gain setting, this mode is not usable for bigger screen sizes.

That said the projector's highlight performance is absolutely breathtaking to look at and likely one of the best in the world - if not the best. It easily competes with JVC's NX7 when it comes to highlight performance and is second only to the HU810PW. With a fully open iris, the daylight scenes of Tenet would blow any user away with an immersion level that is unparalleled. This is one of the reasons why we keep insisting that a dynamic iris would make this a JVC killer. The projector is clearly capable of both deep blacks and mind-blowing highlights, and a dynamic iris could enable just that.

To capture some of that gorgeous highlight performance, however, we would suggest keeping the iris wide open. Yes the blacks will suffer, but you will get the highest "wow factor" out of this projector. One point to note is that our sample did struggle with focus uniformity on the edges - although this is not noticeable during video playback and only during projecting text. HDR performance is also slightly improved over the HU810PW which was a bit on the dim side.

HU710PW's pleasant surprise: color separation

Here is the thing, even though HU710PW boasts 94% DCI P3 vs 97% of its bigger brother and has lower native contrast than the same, it has far better color separation. Every image and demo reel we ran showcased flawless color separation (once calibrated). Adaptive contrast and the color upgrade actually work great as well (they resulted in color oversaturation issues in the HU810PW). We suspect this is due to the fact that the HU710PW has dedicated color channels while its bigger brother does not. If TV-like color vibrance is something you like, you will love the HU710PW.

Image samples of the LG HU710PW 4K laser projectors

LG's incredible contrast and highlight performance are clearly visible in these images (straight from the camera with no additional post processing) - although pictures clearly do not do them justice.

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Conclusion

The LG HU710PW is a masterclass in continued innovation that has world-class highlight performance. This is a projector where you have actual control over the color lumen output and can tweak and tune to your heart's content. It has better blacks than its bigger brother, the HU810PW, and far better color seperation. Where the projector really shines, is highlight performance with the contrast wide open. Sure, blacks will suffer just a tad, but we can assure you your friends will go home raving about the image quality.

For purists that want a pitch-black cinematic experience - it can do that too. Have an ideal dark/highlight ratio in your mind that you wish to get? Just play around with the settings till you achieve just that. With a laser light and LED hybrid light source that will last for 20000 hours and a price tag of just $2,499 it is clear that LG has another winner on their hands. Because of this, we are happy to give them our Editor's Choice Award.

9.4

Wccftech Rating

LG has made its laser projector even better and more affordable for the average home theater enthusiast.