What it is:
General purpose. The TV will be used for a variety of content and usages. Movies at night, TV shows during the day, video games from time to time, etc.
What it is:
Movies in the dark. The TV will be used for watching movies in a controlled environment, directly in front, in a home theater way. Mostly only high quality content, like Blu-rays, UHD Blu-rays, streaming and a little bit of HDR.
What it is:
TV Shows in a bright living room. The TV will be used in to watch TV shows, in a bright room during the day, from multiple viewing positions at different angles. The content watched has an average quality: cable, streaming, SD channels, etc.
What it is:
Sports in a living room. The TV will be used to watch sports during the day, like football or hockey. Usually watched with a group, so from multiple viewing position.
What it is:
Video games. The TV will be used to play video games, directly in front, in a controlled light environment. Usually fast games, like online FPS, where motion blur and input lag is important.
What it is:
HDR Movies and TV shows. The TV will be used to watch 4k UHD HDR content, with a wide color gamut and a high peak brightness. Either via UHD Blu-rays or HDR streaming.
What it is:
HDR Gaming. The TV will be used to play HDR video games using consoles that support it or on current generation gaming PCs. Xbox One S, PS4 Pro, GTX 10 series and AMD RX series graphics cards.
What it is:
PC Monitor. The TV will be used as a PC monitor, from 2-3 feet away, either for productivity purposes or gaming. Sharp text is important, as well as a high resolution.
The JU6400 is the entry point of Samsung's 4k TVs. It doesn't look cheap, has very little blur on movement, and delivers excellent performance for video games. Unfortunately, the picture quality in a dim room is bad (blacks will appear gray), and judder is present on 24p movies.
The Samsung JU6400 is thin, and the overall look of the TV is good. The slim borders and the stand are made of plastic with a brushed steel appearance. The fixed stand is sturdy, and has a small footprint, but is prone to collecting dust.
This isn't a good TV for watching movies in a dim room. The contrast is very low and the blacks will appear gray. The TV also has judder on 24p sources (like Blu-ray) and doesn't have any fancy features like 3D, local dimming, or HDR.
5.4
Contrast
What it is:
Brightness difference between white and black. This is the main component of picture quality.
When it matters:
Always, but especially when watching dark scenes.
Contrast is really poor on the 55" UN55JU6400, and blacks will often appear gray. Those flaws won't be too apparent in a well-lit room. Other sizes of the JU6400 doesn't have this problem.
What it is:
Configuration of the lights of the backlight.
When it matters:
Effectiveness of the local dimming.
Good value:
Full-array/direct lighting is better for local dimming. As for the uniformity of the screen, it depends on the implementation. Some edge-lit TVs have more uniform blacks than some full-array TVs.
What it is:
The maximum luminosity, even if only maintained for a short time, of a white square covering 2% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over SDR signal.
When it matters:
Bright highlights, present on screen for a short time; especially for SDR content.
What it is:
The maximum luminosity, even if only maintained for a short time, of a white square covering 50% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over SDR signal.
Uniformity isn't great, with horizontal and vertical banding that can be seen. The corners are also a lot darker. Those problems could be apparent on playing fields of uniform color.
What it is:
Type of LCD technology used by the TV.
When it matters:
Different technologies have different viewing angle properties.
Good value:
IPS maintains good color accuracy at an angle, but has a poor contrast ratio from in front. VA has great picture quality in front, but loses saturation at an angle.
What it is:
Angle where the colors noticeable shift compared to when viewed from directly in front of the TV. 0 ° means directly facing the TV. Measurements are up to a maximum of 75 °.
When it matters:
Large living rooms with multiple viewing positions.
What it is:
Angle where the brightness drops to 50% of the brightness directly in front of the TV. 0 ° means directly facing the TV. Measurements are up to a maximum of 75 °.
When it matters:
Large living rooms with multiple viewing positions.
What it is:
Angle where the black level drops to 50% of the black level directly in front of the TV. 0 ° means directly facing the TV. Measurements are up to a maximum of 75 °.
When it matters:
Large living rooms with multiple viewing positions.
Like other IPS TVs, the 55" one has a wide viewing angle. Colors remain saturated at an angle, though the picture darkens a bit. Other sizes of the series have worse viewing angle.
Update 01/06/2017: We have changed the methodology of testing. Since this is an old TV which we don't have anymore, we extrapolated the results from 2016 TVs.
What it is:
Number of bits per pixel to represent a specific color. Note: we consider 8-bit with dithering to be equivalent to 10-bit, as long as the 10-bit gradient looks smooth.
When it matters:
HDR content like UHD Blu-ray players. Won't matter for cable TV, regular Blu-ray movies, video game consoles or content displayed from a Windows PC. Those are limited to 8-bit color.
What it is:
TV's color accuracy after a full calibration with a spectrophotometer.
When it matters:
All video on a TV that has been professionally calibrated. This isn't that useful, because most TVs can achieve a pretty good calibration if you spend enough time on them.
The semi-gloss finish doesn't reflect a lot of light, and there is no rainbow around bright objects. The TV can get bright enough for most environments.
The motion on the JU6400 is excellent. Objects will stay defined even when moving at full speed, and details won't be lost in the action. Because of the somewhat average gray uniformity, some dark patches can be seen on long camera pans over the fields.
This is the Samsung TV with the least amount of blur we've seen this year. There is a little bit of overshoot (see the trail to the left of our moving logo), but movement is pretty clear overall.
Combined with its excellent motion handling, the JU6400 is great for video games. Action on the screen is well-defined, and the controls are very responsive. You can still find better options for a dedicated gaming TV, but the JU6400 is near the top.
7.8
Input Lag
What it is:
Delay between input and onscreen reaction.
When it matters:
Video games; when TV is used as PC monitor.
When it matters:
PC productivity and 60 fps gaming.
:
Yes
1080p @ 120Hz
What it is:
120 fps 1080p signal supported.
When it matters:
PC gaming.
:
No
4k @ 30Hz @ 4:4:4
What it is:
Crisp text on 4k @ 30 hz signal.
When it matters:
PC productivity and gaming.
:
Yes
4k @ 60Hz
What it is:
60 fps 4k signal supported.
When it matters:
PC productivity and gaming.
:
Yes
4k @ 60Hz @ 4:4:4
What it is:
Crisp text on 4k @ 60 hz signal.
When it matters:
Productivity and 60 fps gaming in 4k.
:
No
Unlike other 4k Samsung TVs, the JU6400 doesn't do 4k @ 60Hz @ 4:4:4 (there is no 'UHD Color' option). To get Chroma 4:4:4 in the other modes, label the input as 'PC'.
Side Inputs
Rear Inputs
Total Inputs
HDMI
:
3
USB
:
2
Digital Optical Audio Out
:
1
Analog Audio Out 3.5mm
:
1
Analog Audio Out RCA
:
0
Component In
:
1 (shared)
Composite In
:
1 (shared)
Tuner (Cable/Ant)
:
1
Ethernet
:
1
DisplayPort
:
0
IR In
:
0
SD/SDHC
:
0
Inputs Specifications
HDR10
What it is:
Standard HDR format.
When it matters:
Most common format. All UHD Blu-ray discs are required to have it.
:
No
Dolby Vision
What it is:
Better format, due to its dynamic nature.
When it matters:
Currently, only available via streaming.
:
No
5.1 Passthrough ARC Dolby Digital
What it is:
TV can receive and pass Dolby Digital 5.1 signal to receiver via HDMI ARC.
When it matters:
5.1 audio on DVDs and Blu-rays.
:
Yes
5.1 Passthrough ARC DTS
What it is:
TV can receive and pass DTS 5.1 signal to receiver via HDMI ARC.
When it matters:
5.1 audio on DVDs and Blu-rays.
:
Yes
5.1 Passthrough Optical Dolby Digital
What it is:
TV can receive and pass Dolby Digital signal to receiver via digital optical.
When it matters:
5.1 audio on DVDs and Blu-rays.
:
Yes
5.1 Passthrough Optical DTS
What it is:
TV can receive and pass DTS signal to receiver via digital optical.
The sound isn't very accurate, and doesn't have great bass. Still, it can get fairly loud, and there isn't too much distortion.
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.
Poor frequency response especially at higher volumes where pumping and compression may be present. The TV does get relatively loud, but the extension is poor.
There isn't a huge variety of apps, but the Tizen OS feels intuitive. The basic remote makes navigating the smart features less pleasant, but it is useful enough for navigating all the TV settings.
What it is:
Whether you can opt out of the ad services or not. A TV only passes this test if it allows you to remove them completely, not only disable the personalized advertising.
The 55" Samsung UN55JU6400 that we reviewed has a PLS panel (version FD05), which is a sub-category of the IPS family, and which produces grayish blacks, and has a wide viewing angle. If someone comes across a different type of panel used, let us know and we will update our review. Thank you in advance.
Some of our visitors reported that the 40", 43" and 48" version of the JU6400 has VA panels with better contrast ratios and worse viewing angles.
What it is:
General purpose. The TV will be used for a variety of content and usages. Movies at night, TV shows during the day, video games from time to time, etc.
The JU6400 is a mixed bag. It is an excellent option for gaming, great for sports and well-suited for a well-lit family room. Unfortunately, it won't be as good for movie lovers who like to watch TV in a dim room, as the TV has poor blacks and suffers from judder. Depending on your viewing habits it can be great, or bad.
