The LG UH6550 is a "4k" TV with slightly above average picture quality. It has a less accurate RGBW pixel structure which means that although it technically has the correct number of pixels, it can't provide the same level of detail as other more traditional 4k TVs. The contrast ratio is low, and it has poor motion handling but the image remains accurate when viewed at an angle.
The design of the UH6550 is simple, but it looks quite good. The stand is a bit more sleek than most other mid-range TVs and when viewed from the side the TV is quite thin which is good. It is similar to most other similarly priced LG TVs.
The LG UH6550 has an average picture quality. When set in a dark room, blacks are not really deep and tend to look more gray than really black due to the low native contrast ratio and even if the black uniformity is good, some blooming will still be noticed when watching a movie with black letter boxes. Performance will be better in a well lit room, where the low contrast ratio will be less of a problem and because the TV is able to fight glare reasonably. Viewing angle is good and will fit the needs of people with a wide seating area. The HDR performance is limited by the an average peak brightness, poor local dimming and the average color gamut coverage, even if the TV has an excellent color gradient. Don't expect much improvement over SDR content. The upscaling is on par with other LG TVs, which is good especially for cable TV. For sports the dirty screen effect will be noticeable because of the average gray uniformity.
The UH6550 has a local dimming feature, but like on most of other edge lit TVs, it is not really effective. The number of dimming zones is relatively low and they span large vertical zones. When set on 'High', the zones can easily be seen turning on and off following the white dot of the local dimming video. The local dimming also darkens the smaller dots too much. For this reason we don't recommend using this feature while set to 'High'. If you really want to use the local dimming, set it to 'Low' to diminish this darkening effect.
When measured in SDR with local dimming on, the peak brightness is bad. The total brightness of the TV is almost half of what it can reach while in HDR mode and since most of the content that is available is not in HDR, this leaves you with TV that can't get very bright.
The peak brightness is below average. With a HDR signal and with local dimming turned on, the peak brightness of the smaller 2% size windows is almost cut to half of what the average brightness of the TV is. If local dimming is turned off while sending an HDR signal, a general brightness of 355cd/m² was recorded for all size windows.
The gray uniformity is below average. Some large zones are warmer than the rest of the screen and each border is also darker than the rest of the screen. Dirty screen effect is visible while watching content like sport or any other videos with large panning shots over an uniform surface.
The viewing angle is good, the color and contrast is maintained much more than any VA TVs and a bit more than other IPS TVs. This TV would be especially good for people with a wide seating area.
Update: We have changed the methodology of testing. Since this is an old TV which we don't have anymore, we extrapolated the results.
The screen is not very uniform, and so this result is very sensitive to where the spectrophotometer is placed. Prior to calibration the colors are quite inaccurate, especially the blue which follows a very unusual curve. The white balance is a bit too warm. For anyone that cares about the image accuracy a calibration is required.
Although we were able to fix the white balance issues at the location of the spectrophotometer, this isn't representative of the whole screen. Different areas are warmer or cooler than each other, so it wasn't really possible to calibrate it well. Adjusting the color space at all resulted in artifacts when watching normal content, so we left it untouched. As such, we couldn't fix the color issues. You can see our recommended settings here.
In the settings there are options for 'Wide' or 'Extended' color gamut. Although this does increase the saturation of the primary colors, it is not enough for us to consider it a wide color gamut TV. Changing the color gamut to 'Wide' provides the most colors, 'Normal' is suitable for SDR content and 'Extended' is somewhere in between.
No image retention could be detected on the LG UH6550. This is a good result, when comparing to other LG IPS TVs, since they tend to be more prone to image retention. This is particularly good for people looking to use this TV as a PC monitor.
The IPS RGBW pixel structure is the same as what we have seen in most other LG 6 Series TVs. It is slightly less accurate than a traditional RGB structure, and this is most obvious when displaying small vertical lines such as our chroma test here.
The motion handling of the UH6550 is slightly worse than average. Motion blur is visible following any fast moving objects, which may be an issue for sports or gaming. Movies are smooth when played from a 24p source such as a Blu-ray player. From other 60 fps sources some smaller judder is present, but most people don't notice it. The TV has a 60Hz panel which is able to interpolate lower frame rate content for those who enjoy the soap opera effect.
The response time of the TV is quite high, resulting in slightly more motion blur than average. This results in a trail following moving objects, and isn't good for any fast paced content. You can see the flicker of the backlight due to the PWM dimming in the duplications following the logo.
Movies played from a 24p source such as a Blu-ray player or the built in apps are smooth with 'Real Cinema' enabled. Some smaller judder is present when movies are played from 60Hz sources, but most people won't notice this so it isn't an issue.
For SDR content, the input lag is quite low which is great. When a HDR signal is detected the TV switches to different picture settings, with high input lag which is an issue for PS4 Pro or Xbox One S gamers. The TV supports a wide range of resolutions and chroma subsampling, which is good for PC use. Unfortunately the RGBW pixel structure results in some lines appearing jagged at high resolutions.
The input lag varies a lot depending on the source. For SDR users though, the results are quite good. As long as interpolation is disabled and game mode is activated the input lag is low and this shouldn't be an issue, even with chroma subsampling enabled for PC use. With HDR though, the input lag is high as there is no HDR game mode.
Update 12/08/2016: With the newest firmware update (04.30.70) there has been the addition of a HDR gaming mode. In this mode the HDR input lag is lower, and should be fine for HDR gaming. Note that although the TV accepts a 4k @ 60Hz @ 4:4:4 + HDR signal, it can't accurately display the chroma subsampling in any HDR mode, even with the 'PC' icon selected.
The TV supports most of the demanding resolutions for PC monitor use, except a 120Hz input as it only has a 60Hz panel. To enable the bandwidth for 4k @ 60Hz it is necessary to activate the 'HDMI ULTRA HD Deep Color' option for the HDMI port. This is available in the 'General' settings menu. In order to display chroma subsampling, change the input icon to 'PC'. Although it supports chroma subsampling, it is not as clear as most other TVs due to the less accurate pixel structure. This is penalized in the '4k Resolution' section of the review.
The overall sound quality is below average. The frequency response is decent, but gets worse at louder volumes. There is increasing distortion at higher volumes. Even a cheap sound bar is an improvement over the TV speakers.
Note: Sound Quality test for TVs reviewed before 2017 was performed at 75dB, 85dB, and Max SPL. Starting 2017, the target SPL levels have been changed to 70dB, 80dB, and Max dB SPL.
Decent performance. Frequency response is good at lower volumes but as the volume approaches maximum volume, pumping and compression increases. Additionally, this TV does get decently load, and has a good low-end cutoff for a TV.
The UH6550 comes with the latest version of LG's WebOS, the same 3.0 version which is shipped with all of the 2016 LG TVs. It is a significant improvement over previous iterations and works very well. It is one of the most stable TV platforms and although it doesn't have the widest selection of apps, they all feel very stable. It does include the most popular media sources such as Netflix, YouTube and Amazon Video. The interface is very intuitive and easy to use. The USB ports on the TV allow directly plugging in a hard drive to play photos or videos.
The basic remote included with the TV is the same as the one included with the rest of LG's 6 series, such as the UH6150. The model code is AKB74915305.
We tested the 55" (55UH6550). For the most part, we expect our review to be valid for the 60" (60UH6550) and 65" (65UH6550).
If someone comes across a different type of panel or if their LG UH6550 doesn't correspond to our review, let us know and we will update the review.
The LG UH6550 has average picture quality, with a low contrast ratio so is better suited to a bright room. Unfortunately for the price you don't get a lot of value so it is hard to recommend. Keep this in mind when viewing our recommendations below.