- Table of Contents
- Intro
- Design
- Picture Quality
- Motion
- Inputs
- Sound Quality
- Smart Features
- Sizes and Variants
- Conclusion
- Discussions
Reviewed on Nov 17, 2015
By Jean-Francois Lize
Samsung JU6400
TV REVIEW
This tv was replaced by the Samsung KU6300
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.
Test Results
| Design | 6.5 |
| Picture Quality | 7.0 |
| Motion | 7.7 |
| Inputs | 7.5 |
| Sound Quality | 6.4 |
| Smart Features | 8.0 |
- Great viewing angle.
- Very low input lag.
- Excellent motion.
- Poor blacks and contrast.
- Judder is present while watching movies even in 24p.
Check Price
Design
Score components:
Subjectively assigned
Score distribution:
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.
Picture Quality
Score components:
- 11% Contrast
- 6% Local Dimming
- 6% SDR Peak Brightness
- 6% HDR Peak Brightness
- 6% Gray Uniformity
- 7% Viewing Angle
- 4% Black Uniformity
- 2% Gradient
- 4% Pre Calibration
- 1% Post Calibration
- 6% 480p Input
- 9% 720p Input
- 11% 1080p Input
- 6% 4k Input
- 4% Color Gamut
- 4% Color Volume
- 1% Image Retention
- 5% Reflections
- <1% 3D
Score distribution:
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.
Score components:
- 100% Native Contrast
Score distribution:
Native Contrast
:
706 : 1
What it is:
Ratio of the white brightness divided by the blacks measured on our checkerboard test pattern with a white target of 100 cd/m².
When it matters:
Dark scenes in a dark room.
Good value:
> 3,000
Noticeable difference:
500
Score distribution:
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.
0
Local Dimming
What it is:
The lights behind the LCD layer adapt to the picture displayed, improving the contrast ratio.
When it matters:
Dark scenes viewed in a dark room.
Score components:
Subjectively assigned
Score distribution:
Local Dimming
:
No
What it is:
Whether it has a feature that controls the LEDs behind the LCD layer, to match the picture and darkens the dark portion of it.
When it matters:
On LED TVs only. Dark scenes viewed in a dark room.
Backlight
:
Direct
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.
6.0
SDR Peak Brightness
What it is:
How bright the screen can get. Measured with local dimming and with SDR content.
When it matters:
Bright living rooms; bright objects; SDR content.
Score components:
Score distribution:
SDR Peak 2% Window
:
271 cd/m2
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.
Good value:
> 400 cd/m2
Noticeable difference:
100 cd/m2
Score distribution:
SDR Peak 50% Window
:
271 cd/m2
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.
When it matters:
Bright rooms.
Good value:
> 400 cd/m2
Noticeable difference:
100 cd/m2
Score distribution:
7.1
Gray Uniformity
What it is:
Evenness of colors onscreen (not just gray).
When it matters:
Solid colors. Sports, panning shots.
Score components:
- 40% 50% Std. Dev.
- 40% 50% DSE
- 10% 5% Std. Dev.
- 10% 5% DSE
Score distribution:
50% Std. Dev.
:
4.062 %
What it is:
Average squared difference of pixels when displaying a mid 50% gray.
When it matters:
Solid colors. Sports, panning shots.
Good value:
< 2.5%
Noticeable difference:
1%
Score distribution:
50% DSE
:
0.184 %
What it is:
High-frequency variance of uniformity. Dark spots on the screen.
When it matters:
Solid colors. Sports, panning shots.
Good value:
< 0.165%
Noticeable difference:
0.025%
Score distribution:
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.
6.9
Viewing Angle
What it is:
Color accuracy when viewed from the side.
When it matters:
Large living rooms with multiple viewing positions.
Score components:
- 20% Color Shift
- 40% Brightness
- 40% Black Level
Score distribution:
LCD Type
:
IPS (only 55")
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.
Color Shift
:
29 °
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.
Good value:
> 50°
Noticeable difference:
10°
Score distribution:
Brightness
:
44 °
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.
Good value:
> 50°
Noticeable difference:
10°
Score distribution:
Black Level
:
75 °
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.
Good value:
> 50°
Noticeable difference:
10°
Score distribution:
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.
6.1
Black Uniformity
What it is:
Evenness of blacks.
When it matters:
Dark scenes viewed in a dark room.
Score components:
- 100% Native Std. Dev.
Score distribution:
Native Std. Dev.
:
2.572 %
What it is:
Average of the squared difference of the blacks.
When it matters:
Dark scenes viewed in a dark room.
Good value:
< 2%
Noticeable difference:
1%, but keep in mind that it varies a lot by unit, even of the same model; yours likely will not end up exactly like ours.
Score distribution:
There is a lot of cloudiness on black screens, and bright flashlighting is present on the right side.
10
Gradient
What it is:
How finely levels of color can be displayed.
When it matters:
Details in shadows, sky and skin tones. Matters more for HDR content.
Score components:
Subjectively assigned
Score distribution:
Color Depth
:
10 Bit
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.
Good value:
10-bit.
Noticeable difference:
1 bit.
7.7
Pre Calibration
What it is:
TV's color accuracy before a full calibration. Only the picture mode and backlight level were changed.
When it matters:
All video on an uncalibrated TV. This represents most people's use cases.
Score components:
- 50% White Balance dE
- 50% Color dE
Score distribution:
White Balance dE
:
5.21
What it is:
Average inaccuracy of shades of gray.
When it matters:
Overall color temperature of all video.
Good value:
< 3
Noticeable difference:
1
Score distribution:
Color dE
:
3.2422
What it is:
Average inaccuracy of colors.
When it matters:
All colors.
Good value:
< 3
Noticeable difference:
1
Score distribution:
Gamma
:
2.25
What it is:
Brightness of shades of gray.
When it matters:
Shadows.
Good value:
Between 2.1 and 2.3 (our target is 2.2)
Noticeable difference:
0.1
9.7
Post Calibration
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.
Score components:
- 50% White Balance dE
- 50% Color dE
Score distribution:
White Balance dE
:
0.62
What it is:
Average inaccuracy of shades of gray.
When it matters:
Overall color temperature of all videos.
Good value:
< 3
Noticeable difference:
1
Score distribution:
Color dE
:
0.2986
What it is:
Average inaccuracy of colors.
When it matters:
All colors.
Good value:
< 3
Noticeable difference:
1
Score distribution:
Gamma
:
2.2
What it is:
Brightness of shades of gray.
When it matters:
Shadows.
Good value:
Between 2.1 and 2.3 (our target is 2.2)
Noticeable difference:
0.1
7.1
Color Gamut
What it is:
How many colors the TV can display.
When it matters:
HDR content. Includes some streaming videos and UHD Blu-rays.
Score components:
- 25% DCI P3 xy
- 25% DCI P3 uv
- 25% Rec 2020 xy
- 25% Rec 2020 uv
Score distribution:
Wide Color Gamut
:
No
What it is:
Whether the TV has an option to enable wide color gamuts.
When it matters:
HDR content. Includes some streaming videos and UHD Blu-rays.
DCI P3 xy
:
79.01 %
What it is:
Coverage of the DCI P3 colorspace on CIE 1931 xy.
When it matters:
DCI P3 content. Includes HDR, UHD Blu-rays.
Good value:
> 90%
Noticeable difference:
5%
Score distribution:
DCI P3 uv
:
84.82 %
What it is:
Coverage of the DCI P3 colorspace on CIE 1976 u' v'.
When it matters:
DCI P3 content. Includes HDR, UHD Blu-rays.
Good value:
> 90%
Noticeable difference:
5%
Score distribution:
Rec 2020 xy
:
56.47 %
What it is:
Coverage of the Rec.2020 colorspace on CIE 1931 xy.
When it matters:
Rec.2020 content. Includes HDR, UHD Blu-rays.
Good value:
> 90%
Noticeable difference:
5%
Score distribution:
Rec 2020 uv
:
64.79 %
What it is:
Coverage of the Rec.2020 colorspace on CIE 1976 u' v'.
When it matters:
Rec.2020 content. Includes HDR, UHD Blu-rays.
Good value:
> 90%
Noticeable difference:
5%
Score distribution:
8.0
Reflections
What it is:
How much light is reflected by the TV.
When it matters:
Bright rooms.
Score components:
Subjectively assigned
Score distribution:
Reflection
:
1.8 %
What it is:
Ratio of ambient light reflected by the TV.
When it matters:
Ambient light in the room.
Good value:
< 1%
Noticeable difference:
0.5%
Screen Finish
:
Semi-gloss
What it is:
Type of coating on the screen.
When it matters:
Bright objects in the direct reflection path (for example, opposite the TV).
Good value:
Glossy is good for ambient light, but not for direct reflections.
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.
0
3D
What it is:
Optional 3D video capability on TV.
When it matters:
3D movies and videos.
Score components:
Subjectively assigned
Score distribution:
Motion
Score components:
- 72% Motion Blur
- 7% Image Flicker
- 14% 24p Playback
- 7% Motion Interpolation
Score distribution:
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.
9.7
Motion Blur
What it is:
Amount of blur on fast movement.
When it matters:
Sports, video games.
Score components:
- 80% Response Time
- 20% Overshoot
Score distribution:
Response Time
:
6.8 ms
What it is:
How quickly pixels can change color.
When it matters:
Fast movement.
Good value:
< 20ms
Noticeable difference:
10ms
Score distribution:
Overshoot
:
1.7 ms
What it is:
When TV’s pixels adjust too far; how quickly they come back.
When it matters:
Fast movement.
Good value:
< 10ms
Noticeable difference:
10ms
Score distribution:
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.
4.8
Image Flicker
What it is:
Luminosity pattern when displaying images
When it matters:
Sports, video games, when TV is used as a PC monitor
Score components:
- 40% PWM Dimming Frequency
- 40% BFI Frequency
- 20% BFI In Game Mode
Score distribution:
PWM Dimming Frequency
:
120 Hz
What it is:
Flickering pattern at different luminosities.
When it matters:
For people sensitive to flickering.
Good value:
N/A or high frequencies (> 300 Hz)
BFI
:
Yes
What it is:
Option to turn screen black between frames
When it matters:
Reduces eye tracking blur in sports or video games
Good value:
Yes
BFI Frequency
:
60 Hz
What it is:
Lowest possible frequency of flickering pattern
When it matters:
Reduces eye tracking blur in sports or video games
Good value:
60 Hz
BFI In Game Mode
:
No
What it is:
Option to insert black frames when in the best settings for gaming
When it matters:
Reducing eye tracking blur for video games
Good value:
Yes
0
24p Playback
What it is:
Whether 24p content can play without any judder.
When it matters:
Only 24p content (mostly just movies).
Score components:
Score distribution:
Judder-free 24p
:
No
What it is:
Judder-free movies over 24p signal.
When it matters:
Blu-ray and DVD movies; 24 hz PC signal.
Judder-free 24p via 60p
:
No
What it is:
Judder-free movies over 60p signal.
When it matters:
Movies from streaming devices (Apple TV, Fire TV, etc.); 60 hz PC signal.
Judder-free 24p via 60i
:
No
What it is:
Judder-free movies over 60i signal.
When it matters:
Movies from cable/satellite boxes.
Judder in movies isn't too noticeable, but this TV cannot eliminate it without the use of the soap opera effect ('Auto Motion Plus').
5.0
Motion Interpolation
What it is:
Also known as 'Soap Opera Effect'. It is an optional feature that increases the frame rate of the video, smoothing movement.
When it matters:
If you like the look of smoothed video. Not everyone does.
Score components:
Score distribution:
Motion Interpolation (30 fps)
:
Yes
What it is:
Whether the TV can take a 30 fps input and heighten the frame rate to at least 60 fps.
When it matters:
30 fps or lower videos. Includes movies, TV shows, some video games.
Motion Interpolation (60 fps)
:
No
What it is:
Whether the TV can take a 60 fps input and heighten the frame rate to at least 100 fps.
When it matters:
60 fps videos. Includes some video games, some sports channels.
Inputs
Score components:
- 86% Input Lag
- 14% Supported Resolutions
Score distribution:
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.
Score components:
Score distribution:
1080p @ 60Hz
:
26.4 ms
What it is:
Lowest input lag possible on TV with a 1080p @ 60Hz input.
When it matters:
Video games and also when TV is used as PC monitor.
Good value:
< 40ms
Noticeable difference:
15ms
Score distribution:
1080p With Interpolation
:
110.7 ms
What it is:
Lowest input lag when the motion interpolation feature is turned on.
When it matters:
When you want to play video games with the Soap Opera Effect enabled.
Good value:
< 40ms
Noticeable difference:
15ms
Score distribution:
1080p @ 60Hz Outside Game Mode
:
119 ms
What it is:
Input lag in picture modes other than the specific game mode.
When it matters:
For playing video games while retaining access to all features of the TV.
Good value:
< 40ms
Noticeable difference:
15ms
Score distribution:
1080p @ 60Hz @ 4:4:4
:
34.9 ms
What it is:
Lowest input lag possible on TV when displaying 1080p @ 60Hz @ 4:4:4
When it matters:
PC monitor.
Good value:
< 40ms
Noticeable difference:
15 ms
Score distribution:
The very low input lag is among the best you can find when you set the TV to game mode. In PC mode, the input lag is still good, at 34.9 ms.
6.0
Supported Resolutions
What it is:
Different resolutions supported by TV.
When it matters:
PC monitor usage.
Score components:
- 20% 1080p @ 60Hz @ 4:4:4
- 20% 1080p @ 120Hz
- 20% 4k @ 30Hz @ 4:4:4
- 20% 4k @ 60Hz
- 20% 4k @ 60Hz @ 4:4:4
Score distribution:
1080p @ 60Hz @ 4:4:4
:
Yes
What it is:
Crisp text on 1060p @ 60 hz signal.
When it matters:
PC productivity and 60 fps gaming.
4k @ 30Hz @ 4:4:4
:
Yes
What it is:
Crisp text on 4k @ 30 hz signal.
When it matters:
PC productivity and gaming.
4k @ 60Hz
:
Yes
What it is:
60 fps 4k signal supported.
When it matters:
PC productivity and gaming.
4k @ 60Hz @ 4:4:4
:
No
What it is:
Crisp text on 4k @ 60 hz signal.
When it matters:
Productivity and 60 fps gaming in 4k.
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'.
HDR10
:
No
What it is:
Standard HDR format.
When it matters:
Most common format. All UHD Blu-ray discs are required to have it.
Dolby Vision
:
No
What it is:
Better format, due to its dynamic nature.
When it matters:
Currently, only available via streaming.
5.1 Passthrough ARC Dolby Digital
:
Yes
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.
5.1 Passthrough ARC DTS
:
Yes
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.
5.1 Passthrough Optical Dolby Digital
:
Yes
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.
5.1 Passthrough Optical DTS
:
Yes
What it is:
TV can receive and pass DTS signal to receiver via digital optical.
When it matters:
5.1 audio on DVDs and Blu-rays.
Sound Quality
Score components:
Score distribution:
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.
6.0
Frequency Response
What it is:
Sound level at different frequencies.
When it matters:
For balanced sound.
Score components:
- 8% Std. Dev. @ 70
- 15% Std. Dev. @ 80
- 22% Std. Dev. @ Max
- 18% Max
- 37% Low-end Cutoff
Score distribution:
Std. Dev. @ 70
:
5.47 dB SPL
What it is:
Variance of the sound level at different frequencies.
When it matters:
70 dB.
Good value:
< 4 dB
Noticeable difference:
2 dB
Score distribution:
Std. Dev. @ 80
:
5.29 dB SPL
What it is:
Variance of the sound level at different frequencies.
When it matters:
80 dB.
Good value:
< 4 dB
Noticeable difference:
2 dB
Score distribution:
Std. Dev. @ Max
:
7.10 dB SPL
What it is:
Variance of the sound level at different frequencies.
When it matters:
Max volume.
Good value:
< 4 dB
Noticeable difference:
2 dB
Score distribution:
Max
:
91.2 dB SPL
What it is:
Max volume on the TV at a distance of 1 meter.
When it matters:
For listening to loud audio.
Good value:
> 90 dB
Noticeable difference:
2 dB
Score distribution:
Low-end Cutoff
:
134 Hz
What it is:
How low of a frequency at which the bass starts.
When it matters:
Movies; gaming.
Good value:
< 50Hz
Noticeable difference:
10Hz
Score distribution:
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.
7.2
Total Harmonic Distortion
What it is:
Pureness of a single frequency.
Score components:
- 20% Distortion @ 70
- 40% Distortion @ 80
- 40% Distortion @ Max
Score distribution:
Distortion @ 70
:
0.009
What it is:
Amount of distortion.
When it matters:
70 dB.
Good value:
< 0.100
Noticeable difference:
0.100
Score distribution:
Distortion @ 80
:
0.010
What it is:
Amount of distortion.
When it matters:
80 dB.
Good value:
< 0.100
Noticeable difference:
0.100
Score distribution:
Distortion @ Max
:
0.053
What it is:
Amount of distortion.
When it matters:
85 dB.
Good value:
< 0.100
Noticeable difference:
0.100
Score distribution:
Very good distortion results. There is a noticeable increase under maximum load, but remains with-in the limits.
Smart Features
Score components:
Subjectively assigned
Score distribution:
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.
Check out our full review of Samsung's smart features.
0
Ads
What it is:
Whether or not ads can be found on the TV's smart platform.
When it matters:
When using the smart features.
Score distribution:
Ad-free
:
No
What it is:
The TV's ability to provide an ad-free experience.
When it matters:
When using the smart features.
Opt-out
:
No
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.
When it matters:
When using the smart features.
Differences between Sizes and Variants
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.
Conclusion
SEE PRICE
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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.
