TCL A400 PRO vs LG OLED C6 (WOLED)

The TCL A400 Pro is a moderately bright TV. Its peak brightness reaches around 600 nits. That level already allows for a real HDR effect and in many films it does deliver a noticeably more appealing picture than in SDR. However, it’s not a level that dazzles by brightness alone. The A400 Pro is not one of those TVs that bombard the viewer with a powerful flash in every dramatic scene. The biggest limitation is visible with small bright elements on a dark background. Because of fairly aggressive zone control, the TV can significantly reduce their brightness, in extreme cases down to around 100 nits. That means small lights, sparks, stars or single highlights can be much less visible than they should be. It should be added, though, that this isn’t done without reason. The A400 Pro does this to keep black levels as deep as possible and to limit the halo effect around bright objects. It’s a deliberate compromise: the TV more often opts for deeper blacks rather than maximising point highlights. On the one hand this is understandable, especially given a limited number of dimming zones, but on the other you should be aware that the HDR effect won’t always be as strong as the peak brightness alone might suggest.

On the plus side, the colours are a strength. The PFS LED filter used here, marketed by the manufacturer as QLED, delivers suitably saturated colours. Our measurements showed about 94% coverage of the DCI-P3 gamut and around 74% of BT.2020, which is a solid result for this class.

The HDR performance of the LG C6 is really very good. LG Display’s new WOLED panel has mainly brought a significant increase in brightness. In our unit we measured around 1500 nits and, importantly, the TV can show similar values in many normal movie scenes as well. That gives HDR real punch. Bright highlights, lamps and sunlight can be genuinely intense, and most HDR movies simply look very impressive. Of course it’s still an OLED, so brightness falls in scenes with a lot of white. The fifth scene from the movie The Meg illustrates this well, where the C6 reached around 600 to 700 nits. That’s still a very good result, but it also shows the new panel hasn’t shed all the limitations typical of OLEDs.

Colours

When it comes to colours, it’s also hard to raise major objections. The C6 covers about 99% of the DCI-P3 gamut and roughly 75% of BT.2020. In practice colours are very saturated and, importantly, stable regardless of the scene. That’s worth emphasising, because not every TV behaves the same in this respect. In some RGB Mini LED models colour saturation can depend more strongly on image brightness. A wider colour gamut today is mainly offered by QD-OLED TVs and new SQD models with a new generation of quantum dots. However, the C6 still performs very strongly here and is able to produce suitably saturated colours in most movie scenes.

As usual, we carried out colour measurements in the best‑tuned picture mode, Filmmaker Mode, the one intended to be closest to the creators’ intentions. The A400 Pro, of course, also offers other picture modes, but in practice they show much larger colour errors and interfere more with the image character. So we won’t cover them in detail in this part of the review. How does the factory colour reproduction fare? In short: really very well. In fact, looking at our measurements, it’s excellent. Both the white balance and the luminance response were set surprisingly precisely. The errors were so small that during the measurements we genuinely rubbed our eyes in surprise. Such good factory settings don’t happen often, even in televisions running Filmmaker Mode. All the more reason to praise TCL, because the A400 Pro straight out of the box can produce an image very close to how the source material should look. The results were so good you could easily think someone had already given this unit extra attention and tried to calibrate it. Our one bit of nitpicking comes down to a single issue. In SDR material the image was slightly brighter than the reference for a dark room, because the factory gamma was set closer to 2.3 than 2.4. It’s not a large error and most viewers probably won’t even notice it. We should note, however, that we are talking about our specific test unit. There can always be some variation in factory colour between individual units, production batches or screen sizes. We do not assume every A400 Pro will look identical straight out of the box.

Right out of the box the LG C6 is quite well set up, especially if you choose the Filmmaker mode. In SDR material the white balance is decent, although as brightness increases there is a slight lack of red. The image becomes a bit cooler, but not enough for it to be very noticeable during normal viewing. More is happening in the brightness characteristic. Gamma is a little low and instead of holding at 2.4, for a large part of the range it sits closer to 2.1–2.2. In practice the C6 slightly brightens midtones. Shadows are therefore more readable, but the image loses some depth compared with how it should look in a darkened room.

In HDR the situation is a bit more interesting. The start of the greyscale looks very good, but from about 20–30% brightness the white balance starts to drift increasingly. As brightness rises there is more red and a noticeable lack of blue. In the brightest sections the difference is already significant and also affects the reproduction of some colours. The EOTF curve itself is followed quite well through most of the range. The C6 only tends to slightly brighten the image, which we also saw in our film comparisons. The largest deviation appears around the brightest parts, where the TV starts adapting the signal to the panel's capabilities.

The factory Filmmaker setting in HDR is therefore not perfect, but overall performs well. The biggest area for improvement is the white balance, especially at high brightness.

Despite the outstanding factory tuning, we couldn't resist checking how the TCL A400 Pro would respond to professional calibration. With such a strong starting point, we were especially curious whether we could squeeze even more from this TV. And here we have to boast: we managed to bring our sample to absurdly low colour errors. Results below 1 are something you don't see every day, even on very good TVs. Such outcomes are more often associated with professional reference monitors than with a lifestyle TV for the living room. In terms of white balance and colour reproduction, the A400 Pro after calibration simply excelled. The only thing we can pick on after closer analysis concerns the brightness response. The TV can vary the luminance level depending on the content being displayed, and quite often the picture is a little darker than it should be according to the reference. This most likely stems from the way the Mini-LED backlight and the local dimming algorithms work in this model. That said, it doesn't ruin the overall impression, because in terms of colour precision the A400 Pro after calibration reached a level that was genuinely hard to expect.

LG TVs have long responded very well to calibration, and the C6 is no exception. After adjustments we managed to set the white balance practically perfectly, and most colour errors fell below 3, often down to around 2. In practice this means very accurate colour reproduction in both SDR and HDR. An interesting detail only appeared with the HDR brightness response. On a classic EOTF chart everything looks almost perfect and at first glance it would be hard to find fault. Only when we measured the TV’s behaviour using filters based on real film scenes did it become clear that the C6 has a slight tendency to artificially boost image brightness.

It’s not a huge difference and many viewers may even see it as a positive, because HDR looks a bit more striking as a result. From the point of view of fidelity to the source material, however, it’s not ideal — some scenes are simply a touch brighter than the filmmaker intended. Interestingly, this is rather unusual for LG. In previous generations the brand’s TVs typically held very closely to the reference picture curve after calibration. The C6 is still very close to the standard, but that subtle brightness 'boost' can indeed be noticed in films and TV series.

Digital image processing is unfortunately one of the weaker points of the TCL A400 Pro. That does not mean the TV performs badly, but it’s hard to call it anything clearly above standard. The upscaling itself is acceptable: edges are fairly well smoothed, the picture does not look overly sharp or “pixelated”, and lower-quality material can be watched without major discomfort. At the same time the overall image has a slightly soft character and you don’t see the kind of precision that the best image processors in more expensive TVs can offer.

Handling of tonal transitions caused by heavy compression is much worse. TCL equipped the A400 Pro with a “Gradual Smoothing” feature that in theory should reduce visible colour banding and artefacts in lower-quality material. In practice, however, its effectiveness is very limited. It does not improve tonal transitions in any noticeable way, and at higher settings it can further smooth image detail, giving it an artificial, slightly blurred character. For that reason we think it’s best to leave this feature off. The A400 Pro copes decently with basic image scaling, but if you often watch heavily compressed material with visible posterisation, this model will not be one of the best choices.

Here the LG C6 has taken a really big step forward. The TV uses the same processor found in the flagship G6, and in terms of image processing the two models are very close. That's a big plus, because in this area LG's processor this year performs excellently. The "Smooth Gradation" function works particularly well. With heavily compressed material it can effectively hide ugly tonal banding and artefacts that often appear, for example, in lower-quality streaming. It's best to leave it on the "Low" setting. Then the improvement is clear, and the TV doesn't yet start blurring fine detail. Higher levels smooth the image more aggressively, but can already remove some of the natural texture of objects on screen. Upscaling itself also performs very well. Lower-resolution content is properly sharpened, edges look clean, and the processor quite effectively reconstructs fine details. In that respect the C6 is really close to LG's best TVs and the differences compared with the G6 are small.

The TCL A400 Pro is equipped with a 144 Hz panel, but in practice we're most interested in how it performs at 120 Hz. That's the refresh rate most consoles, as well as many sports broadcasts and high-motion sources, are limited to today. In that range the TV performs quite well. Motion clarity is really good, especially after properly configuring the motion smoothing. The 'Motion Clarity' function improves smoothness. Its settings include two sliders that let you tailor the motion smoothing to your preferences, separately for low-frame-rate and high-frame-rate content. This allows you to achieve either a more cinematic look or a noticeably smoother image. If you don't want to fiddle with manual configuration, you can use built-in presets such as Low, Medium, High, Cinema or Nature.

The LG C6 features a panel with a maximum refresh rate of 165 Hz, which is great news especially for gamers using a powerful PC. For movies, sport and consoles we’ll of course be limited to 120 Hz at most, but even then it’s hard to fault the motion clarity. As you’d expect from an OLED, the panel’s response time is near-instant. Moving objects therefore don’t leave the characteristic smearing you still see on LCD TVs. This is especially noticeable in sport and fast-paced games, where the picture remains very clean even during dynamic movement.

For movies and TV, LG has also included a motion smoothing system called TruMotion. In the user settings you’ll find two separate sliders. De-Judder is primarily for low-frame-rate material, namely movies and TV series at 24 fps. You can use it to slightly reduce the characteristic judder or increase it if you prefer a much smoother picture. De-Blur, on the other hand, is useful for higher-frame-rate content, mainly sports broadcasts and 50/60 fps TV.

In terms of gaming features the TCL A400 Pro performs brilliantly. The TV has practically everything you’d expect from a gaming TV today: support for 4K at high refresh rates, VRR, ALLM, correct implementation of HDR formats in games, including Dolby Vision, and HGiG. That means it works well with both next‑gen consoles and PCs. Another plus is the inclusion of a Game Bar, a dedicated panel with the most important settings for gamers. From it you can quickly check basic information about the signal, refresh rate or active features, and customise the appearance and behaviour of some settings to your preferences. It’s a solution that may not change picture quality by itself, but it greatly improves the convenience of using the TV while gaming. The only thing to criticise is the number of full HDMI 2.1 ports. The A400 Pro has only two such ports out of four, and one of them also serves as eARC. In practice this means that if you want to connect two next‑gen consoles and a soundbar you may run into some limitations. In that scenario you’ll need to either swap devices or use extra equipment, such as an AV receiver or a soundbar with HDMI inputs. Even so, it’s hard not to rate the A400 Pro very highly as a gaming TV. The gaming feature set here is genuinely powerful.

LG has long focused heavily on gamers, and the C6 essentially lacks nothing important. The TV supports 4K at 120 Hz from consoles, and when connected to a PC it can even run at 165 Hz. On top of that there’s VRR from 40 to 165 Hz, ALLM and a properly functioning HGiG. Another big plus is support for Dolby Vision in games, so the Xbox Series X can use that format without giving up game mode. The package is rounded out by the Game Bar, which lets you quickly check key signal parameters and change settings without leaving your game. In terms of features alone, the C6 is one of those TVs it’s really hard to fault. Whether you play on PlayStation, Xbox or PC, practically everything you could expect from a modern gaming TV is available here.