The Super UHD LG SK 9000 is a 4k TV with very good performance for a range of usages. The picture quality is good in a bright room, and the TV can get bright to overcome glare. It also has great reflection handling, and the image remains accurate when viewed at an angle. Unfortunately, the dark-room performance is sub-par as the native contrast ratio is low and blacks appear gray, despite the full-array local dimming.
The design of the LG SK9000 is very similar to last year's SJ8500. It has the same familiar curved stand, although it is a bit thinner this year and there is a bit more flex to the stand. The color of the frame is more uniform, with a black back instead of the white back of last year's model. There are some practical limitations as there is only very basic cable management and the stand does not allow you to place a soundbar directly in front of the TV.
The stand is curved and looks very similar to last year's SJ9500. It has a slightly darker metal finish and is slightly narrower. The stand does wobble a bit if the floor shakes.
Footprint of the 55" TV Stand: 9.8" x 32.5"
The borders of the TV are thin, and look great. Similar to the SJ9500, the bezel does not surround the LCD panel. The panel is attached on top of the frame and could be damaged if knocked on the side. Care should be taken when moving the TV, as it could be damaged if knocked, similar to what happened to our SJ8500.
The TV has an average thickness but appears thin when viewed from the side due to the gentle angles of the back. It does not stick out when wall mounted.
The TV runs fairly cool. The full array backlight results in a more uniform temperature throughout the back body of the TV. No part of it gets warm enough to cause any issues.
Good build quality. We noticed a small gap between the main panel and exterior bezel, but this should not be an issue. Like the SJ8500, the LG 55SK9000 is almost entirely plastic, but there isn't too much flex.
The LG SK 9000 produces a good picture quality. The native contrast ratio is decent, in dark rooms blacks will be grayer. It has a full array local dimming, but the algorithms are not responsive enough and we don't recommend using it on 'High'. It is much brighter than the SJ8500, but very small highlights get dimmed by the local dimming feature, which is the opposite of what should happen. It has an IPS panel and has a mediocre viewing angle, better than VA panels like the Sony X900F but worse than OLED panels like the LG C7. It also has excellent reflection handling, so it is a good choice for a variety of room types. The gray uniformity is decent, but there is noticeable dirty screen effect which is not good for sports fans.
The native contrast ratio on the SK9000PUA is decent, as is typical of IPS panels. When in a dark room, blacks will look more gray than black. This is less noticeable when in a brightly lit room.
The local dimming feature is ineffective at increasing the contrast ratio.
The local dimming feature on the SK9000 is not responsive enough. It reacts too slowly to moving highlights, and the dimming zones turn on and off too late. It is very similar to the Vizio M Series 2017. We do not recommend using the 'High' setting. 'Medium' or 'Low' work best depending on personal preference.
Very good SDR peak brightness, bright enough for most rooms. Highlights appear dim, this is due to the poor local dimming feature. If you find highlights too dim, set the 'Local Dimming' setting to Low or Off.
This test was done with the 'Contrast' set to '90', which is our recommended value to get the brightest TV possible without causing white crush.
Decent peak HDR brightness. Very small highlights are only noticeable in the sense that they are dimmer than the rest, again a symptom of the poor local dimming. Real scenes are bright enough for most rooms, although still far from the target 1000 cd/m² to fully appreciate HDR content.
Decent overall gray uniformity on the LG SK 9000. The sides of the screen are darker than the rest, but this is not as noticeable as when it is darker in the center. There is noticeable dirty screen effect in the center; this will be especially noticeable when watching sports.
Mediocre viewing angle on the SK9000, far better than most TVs with VA panels, but far worse than TVs with OLED panels. Colors and brightness shift when viewing off angle, making this TV an okay, but less than ideal choice for a room where people will frequently be watching from the side of the TV.
Poor black uniformity on the SK9000. When local dimming is off, there is noticeable backlight bleed across most of the screen.
With local dimming set to 'High', there is visible blooming around the image. The full array local dimming on the SK9000 is turning the zones off, but the results are much worse than other FALD TVs like the Sony X900F.
Decent reflection handling on the SK 9000, identical to the SJ8500. The semi-gloss finish diffuses reflections a bit, reducing their intensity. These results should be fine for most rooms.
The most accurate results out of the box were obtained with the 'Expert (Dark Room)' picture mode. Color and White Balance dE were good, but the color temperature was cold, giving everything a slightly blue tint. The color and white balance delta is low enough that most people won't notice.
Excellent white balance after calibration. Color dE was still a bit high, as the Color Management System in the SK9000 was not very effective at correcting the blue errors. Gamma is very close to our target, shifting a little off target at the low and high end of our inputs.
You can see our recommended settings here.
There were no obvious issues upscaling older 480p content like DVDs on the LG SK9000.
720p content is scaled well on the SK 9000 with no obvious over softening or artifacts.
Good coverage of the P3 color space, the TV is able to display a wide color gamut.
The HDR EOTF in the 'Technicolor Expert' picture mode is too bright for most of our PQ curve, and rolls of gradually at the peak brightness of the TV. The 'PC' and 'Game' EOTF curves are very similar to that of 'Technicolor Expert', which is good.
When displaying HDR content in 'PC Mode', the SK9000 does not properly detect the wide color gamut so colors appear washed. This is the same as the C8.
Decent color volume, but the LG 55SK9000 is unable to produce deep, dark blacks due to its poor contrast ratio and ineffective local dimming. It is also inconsistent in producing bright saturated colors. Color volume is worse than last year's SJ8500.
There were some issues with the SK9000's gradient handling that are not reflected in our testing score. Large areas of near-uniform color showed large areas of banding, worse than the C8. This can be reduced by enabling the TV's 'MPEG Noise Reduction' feature, which enables the gradient smoothing feature of the SK 9000. This helps reduce banding but also causes a loss of detail.
The TV does show some signs of image retention. Only a faint outline of the logo is visible, and it is completely gone before 2 minutes recovery. It is an improvement over the SJ8500, and there is not enough persistence for it to be an issue for most people.
While IPS panels can have some temporary image retention, there doesn't appear to be any risk of permanent burn-in as seen in our long-term test.
The LG SK9000PUA has great motion handling. The response time is slightly improved over the SJ8500, resulting in fluid motion with a short motion trail and low stutter with 24 and 60 fps content. The backlight has been completely redesigned over the SJ8500 and 9500, but there is still noticeable flicker when dimming the backlight. The TV adds black frame insertion, and the TV can reduce the flicker frequency to 60Hz, which helps motion appear more fluid. Movies played from any source appear smooth, although the TV is inconsistent in its ability to remove judder from 60 fps content.
Excellent response time on the LG 55SK9000PUA, great for watching sports or fast paced movies. Most of the blur visible in the photo is caused by 60 fps persistence when there is no flicker, but there is a small motion blur trail behind the logo. There is some overshoot on the 100% transitions but it is minor and should not cause any ghosting. Only a short trail can be seen following fast-moving objects.
The SK9000PUA uses PWM to dim the backlight, which helps to clear up motion slightly, but results in some duplications following fast-moving objects, as can be seen in the motion blur box photo. This causes the backlight to flicker, starting at any backlight setting other than '100'. It uses a different type of PWM dimming than the SJ8500, so it is a bit less noticeable. People sensistive to flicker should consider a nearly flicker-free alternative, like the Sony X900F.
When 'Motion Pro' is enabled, the backlight flickers to match the refresh rate of the content on the screen to reduce persistence blur. With 120 Hz content the natural refresh rate of the backlight is better, so Motion Pro' must be set to Off.
The SK 9000 has a native 120hz panel and can interpolate lower frame rate content up to 120 fps. Motion interpolation can look very strange to people, and in scenes with fast motion, there are some artifacts.
To enable motion interpolation (also called the Soap Opera Effect) set 'TruMotion' to 'User'. For a 30fps source increase the 'De-Judder' slider, and for a 60fps source increase the 'De-Blur' slider.
The LG SK9000PUA displays 60 and 24 fps content without stutter. The response time of the LCD results in smooth motion even in long panning shots.
The SK9000PUA is able to consistently remove judder from 24 fps content, but is inconsistent in its handling of 60 fps content.
To enable this feature, for any content, the 'Real Cinema' option must be turned on.
Update 05/02/2018: We retested 24p judder over 60p on the SK9000 and it correctly passed the test.
The SK 9000 does not support any of the variable refresh rates technologies such as G-Sync, FreeSync, or the native VRR which will be available in HDMI 2.1.
Great low input lag on the LG SK9000. The input lag is low on any supported resolution except in 4k with HDR enabled, although it is still low enough for most gamers. It supports chroma 4:4:4 and 1080p @ 120 Hz, great for use as a PC Monitor. Like the C8, it does not support 1440p resolution.
Excellent low input lag on the SK 9000. Strangely, the input lag is slightly higher on 4k content with HDR enabled (this is the case with the C8 too), but it is still low enough that HDR games will be responsive for most games.
There were no issues with most common resolutions. The LG 55SK9000 does not support 1440p resolution. When in PC Mode with HDR enabled, the TV does not properly support 4:4:4 color and colors appear washed out. In PC Mode a sharpness setting of '0' is the true 0 level.
The SK9000 does not have a component input. It supports composite input via the included adapter.
The TV does not have an analog audio output. To connect a wireless headphone you will need a digital to analog converter like this one.
Update 02/27/2019: While the TV doesn't support Atmos passthrough via a Dolby TrueHD carrier signal (common in Blu-ray disks), it is advertised as supporting Atmos passthrough via Dolby Digital Plus, which is the Atmos format used by some sources like Netflix; our testing confirmed this passthrough on the LG C8. We expect this to be true for the LG SK9000.
The sound quality of the LG SK9000 is decent for a TV. The frequency response is fine, and the TV can get loud without producing too much distortion. Despite this, it is no match for a dedicated surround sound system or even a cheap soundbar. It should be noted that this TV was tested with the Magic Sound Tuning enabled.
Decent frequency response for a TV. It can get very loud, but there is some dynamic range compression as the volume is increased. The low frequency extension is good, much better than most TVs, so it can produce a decent amount of bass. However, the room correction system (Magic Sound Tuning) wasn't able to correct the modes of our test room (the bumps between 200Hz and 300Hz).
The harmonic distortion of the TV is slightly better than average. It is contained at lower volumes, and even at maximum it isn't too bad. The sharp distortion peaks at around 2k and 7k can make the sound of these frequencies a bit harsh.
The LG SK9000 runs the latest version of LG's smart operating system, webOS. It has a decent selection of built-in apps, and the LG content store provides quick access to thousands of third-party apps, although it is not as good as the Google Play Store found on Samsung or Sony TVs. The remote is compact and well built. The design is not as polished as the one found with high-end Samsung or Sony TVs, but it works well. The new voice control functions are very powerful and work well, and can interface with a variety of other devices.
The webOS interface is very similar to last year's model, with the inclusion of the improved search functionality. The menu is very fast and responsive, although the less powerful α7 processor in the SK9000 means slightly more lag than the C8 with its more powerful α9.