The TCL 4-Series S425 Roku Smart TV is a decent TV with decent picture quality. It can display deep blacks thanks to its high native contrast ratio, but lacks a local dimming feature to improve dark room performance. It has good reflection handling, but limited brightness both in SDR and in HDR, and doesn't perform well in a bright room. It does not have a wide color gamut and can't deliver HDR content with vivid colors and bright highlights. It has a very fast response time, and fast-moving content has only minimal blur trail. The input lag is very low, and this will please gamers and PC users.
The TCL S425 has a decent design. It has a wide plastic stand that supports it well, but the TV will wobble if nudged. The back of the TV is very similar to last year's TCL S405. The top half is metallic, whereas the bottom part and the body are plastic. It is not very thick and will not protrude much if wall-mounted. The build quality is decent, and you should not have any issues with it.
The stand of the TCL S425 is plastic and supports the TV well. It is black and almost as wide as the TV. Last year's TCL S405 had a very similar stand, but with a silver finish. The legs cannot be reversed, and the TV will wobble if nudged.
Footprint of the 55" model stand: 32.2" x 7.3"
The back of the TV is plain. The top part is metal, whereas the bottom half and the rest of the body are plastic. The TCL S425 is available in many sizes and not all of them fit the same VESA mount size. Check here to see which VESA mount size is suitable for each TV size.
There is no cable management.
The borders are plastic, very plain, and have an average thickness.
The TV has an average thickness when viewed from the side, and it will not stick out much if wall-mounted.
The build quality is decent. There are no gaps or loose ends, and although the TV does not have a premium look, you should have no issues with it.
The TCL 4-Series has a decent picture quality. It has a high native contrast ratio that delivers deep blacks in a dark room but unfortunately, it lacks a local dimming feature to further improve dark room performance. The S425 cannot get very bright and it is more suitable for a dim room. It can handle reflections well but has narrow viewing angles and it is not suitable for a room with a wide seating arrangement. It doesn't have a wide color gamut and can't deliver HDR content with vivid colors and highlights that pop. Finally, the gray uniformity is decent, but some sports fans might find the amount of dirty screen effect bothersome.
The native contrast ratio of the TCL S425 is excellent. Blacks look deep in a dark room and this great for the picture quality. It is a significant improvement over last year's TCL S405. Unfortunately, the TV lacks a local dimming feature and can't improve the appearance of blacks further.
The TCL S425 does not have a local dimming feature. The video is for reference only.
Disappointing SDR peak brightness for the S425. The performance is in the same ballpark figure as last year's TCL S405. This TV is okay for a moderately lit room, but it is not suitable for a bright room. Except for small highlights, the brightness remains unchanged no matter the scene, and this is good.
We performed our measurements after calibration with picture mode set to ‘Movie.’ Different settings may produce a brighter picture.
You can check our settings page to see how to set the brightness.
The TCL S425 has poor HDR peak brightness and can't display bright HDR highlights. Just like in SDR, the brightness remains unchanged no matter the scene. This is a similarly bad performance to last year's TCL S405.
We performed our measurements without calibration with picture mode set to ‘dark HDR' and 'brighter.' Different settings may produce a brighter picture.
You can check our settings page to see how to set the HDR settings.
The TCL 4-Series has decent gray uniformity. The corners are a little darker, and some dirty screen effect can be seen at the center of the screen, which might disappoint sports fans. Unfortunately, in near-dark scenes, there are noticeable uniformity issues on both sides of the screen, but the uniformity is better in the center.
The S425 has bad viewing angles. This is typical for VA panel TVs. As soon as you move off center, the image loses accuracy as gamma shifts, black levels rise, and colors start to wash out. This is similar behavior to last year's TCL S Series S405. This TV is not a good choice if you have a room with a wide seating arrangement. If viewing angles are important to you, then check out the LG UK6300.
The black uniformity on the TCL S425 is decent. There is visible backlight bleed at the edges which, however, is only noticeable when you watch a very dark scene in a dark room.
The handling of reflections on the TCL 4-Series is good. The TV has a semi-glossy finish that limits indirect reflections. You should have no problem placing this TV in a room with many small light sources. However, if you place it across from a large window, reflections might become bothersome.
Unfortunately, the out-of-the-box color accuracy for the TCL S425 is disappointing. The errors we measured both in the white balance dE and in the color dE are large. The color error especially might be noticeable by many. The TV is clipping reds and whites when not in PC mode. In order to see a significant improvement, you would have to lower the contrast a lot, but we do not recommend it as it affects the picture quality. The color temperature is warmer than the 6500K target, and thus the image has a slight reddish and yellow tint. The gamma does not follow the target, and thus dark scenes are significantly darker than they should be.
After calibration, the accuracy of the TCL S425 is excellent. It is almost impossible to spot any remaining white balance inaccuracies. On the other hand, some color inaccuracies, mainly in the reds and the greens, remain after calibration and some enthusiasts might be able to spot them. Just like with other TCL TVs, calibration is only possible via the mobile app, but you still need to use a colorimeter.
You can see our recommended settings here.
Upscaling of 1080p content such as Blu-rays or game consoles looks good with no obvious issues.
The TCL S425 does not have a wide color gamut. The true color gamut of the TV is shown by the maximum red, green, and blue in the Rec 2020 gamut picture. Unfortunately, all other colors in the Rec 2020 picture and all the P3 colors are undersaturated. We assume that this happens because the TV is prioritizing brightness over color accuracy because it is so dim. These tests were done at 75% brightness stimulus. When we performed the same tests at a dimmer 50% stimulus the accuracy was much better as can be seen in the following images:
The TV's EOTF is dimmer than the PQ curve, and at about 50% stimulus gray it starts to roll off very early to smooth the transition to the TV's low peak brightness. The same performance is found in 'Game' mode as you can see here.
If you wish to make the HDR brighter, you can set gamma to 1.8 in the phone app. This will result in this EOTF which is a little brighter than before.
The TCL 4-Series has mediocre color volume. The TV can't display very dark saturated colors. When the TV is trying to display bright P3 colors, the gamut narrows significantly, probably due to the TV's tone mapping prioritizing brightness over color accuracy because the TV is so dim.
There is no temporary image retention on the TCL S425.
We don't expect VA panels to experience permanent image retention, as the VA panel in our long-term test appears immune.
The motion handling of the TCL S425 is decent. It has a very fast response time, so there is only a little blur behind fast-moving content. Below a certain brightness level, it uses PWM to dim the backlight, which might bother some people. There are no extra features to enhance motion handling, and unfortunately, the TV can only remove judder from true 24p sources.
The response time of the S425 is excellent. Only a short trail follows fast-moving objects. In dark scenes, however, some smearing may be present due to the longer transition between darker shades, such as from 0% to 20%. Nonetheless, this is an improvement over last year's S405.
The TV uses PWM to dim the backlight, but only below 17/100 backlight setting. Backlight PWM dimming results in a 120Hz flicker which might bother some people. This is very different behavior than the TCL S405, which used PWM dimming throughout the entire range of its backlight levels.
Just like last year's S405, the S425 can't reduce its flicker frequency to 60Hz to make the image look crisper. However, at lower brightness levels, its 120Hz PWM backlight does help somewhat to make motion look clearer.
The S425, just like last year's S405, doesn't provide any motion interpolation feature.
The TCL 4-Series has a little stutter due to the very fast response time that results in a higher frame hold time of 24p content, like movies. Unfortunately, the TV does not offer any option to help you reduce stutter.
Unfortunately, the TCL S425 can only remove judder from 24p movies when they are played from 24p sources like DVDs or Blu-rays. 24p movies played from 60p/60i sources like cable, satellite boxes, or even through the native apps will have some judder.
There is no specific feature or option to turn on so as to remove judder from 24p movies on 24p sources. The TV detects it and displays the movie properly.
The S425 has a 60Hz panel and does not support more advanced features such as FreeSync.
The S425 has a very low input lag that will please gamers. It supports the most common resolutions and can display proper chroma 4:4:4 as long as you set the input icon to 'Computer.' When you connect a PC to the TV, it automatically switches and locks to PC mode.
The TCL S425 has excellent low input lag. To get the lowest input lag, you need to switch the Game Mode to 'On.' The Game Mode is available in all picture modes. During our test, there we times where we had to turn off the TV or disconnect and reconnect the HDMI to get the lowest input lag. We assume that this was due to an issue with the HDMI handshake. When we changed to 'Game Mode' it went to an in-between state that had a higher input lag. This should not be a common issue to most users.
When you connect a PC, it is always detected automatically, and you do not have to do anything special to display proper chroma subsampling 4:4:4. To display 4:4:4 through other sources, change the icon to Computer.
The TCL S425 supports most common resolutions at 60Hz, but it can't display any resolution at 120Hz. Chroma 4:4:4 works properly with a PC even if the icon on the input is not set to 'computer.' For other sources, change the icon to 'computer.'
To set an HDMI port to full bandwidth 2.0, follow this sequence: Settings > TV Inputs > HMDI1 (for port 1) > HDMI Mode > HDMI 2.0.
When you connect a PC, the TV switches automatically to PC mode. There is no way to use the TV with a PC and be outside of PC mode.
The S425 supports CEC, but we were unable to make it work with our Blu-ray player.
If you wish to enable Dolby over ARC, you must select the Dolby D/DTS setting.
The TCL has a mediocre sound. It can't get very loud but is able to produce clear and intelligible dialogue. Unfortunately, its bass is lacking and doesn't have any body or thump to it. The TCL S425 has no room correction system but its distortion performance is decent. For a better sound, dedicated speakers or soundbars are recommended.