TCL RM7L vs LG OLED B6

TCL RM7L is a bright TV. In our measurements its peak brightness hovered around 1600 nits. That’s noticeably less than the C7L, which can get close to 2600 nits, but in real-world film scenes the difference between the models isn’t that large. In less demanding shots, where plenty of bright elements appear on screen, the RM7L can sustain around 1000 nits, and sometimes even a bit more, approaching 1500 nits. It performs worse in dark scenes with small points of light; then their brightness can fall to about 500 nits. This behaviour isn’t random. The TV deliberately dims small elements to better control the backlight and preserve higher contrast. This comes at the expense of their intensity, but it’s typical for TVs with local dimming in a similar price range.

Colour gamut coverage

In HDR brightness isn’t the only thing that matters, colour does too. Here the RM7L has a lot to show. Colours are strongly saturated and the wide colour gamut is one of its main strengths. In our measurements it reached about 96% of DCI-P3 and around 83% of BT.2020. It’s worth remembering, though, that on a TV with this kind of backlight the result can vary depending on the scene. On test patterns colours look best, while in films their saturation can be a little lower than on SQD Mini LED or QD-OLED TVs. The backlight design itself is interesting. The RM7L doesn’t use the classic red, green and blue LED set. TCL used two green LEDs and one blue, with red produced via a PFS phosphor. You can see this in spectrometer measurements, but it doesn’t have a major impact on the picture. Colours are still rendered correctly.

LG B6 is a moderately bright OLED. After calibration it reaches around 800 nits, roughly 200 nits more than last year's B5. That's down to LG Display's new budget OLED SE panel. In practice this simply provides a bit more headroom and makes HDR look fuller in many scenes than on last year's lower-end OLEDs. That doesn't mean the B6 has no limitations. In very bright shots, when a large part of the screen is brightly lit, brightness can fall below 400 nits. This behaviour is typical of OLED TVs (especially in this segment), and it's then you see the biggest difference compared with pricier models. All the same, we rate the B6's results as really solid. It's still not a TV built to break brightness records, but the HDR effect is strong enough that films really feel like a step up from ordinary SDR picture.

Colour gamut

Using the OLED SE panel has had some impact on wide colour-gamut coverage. Compared with last year's model the figures have dropped by a few percentage points. DCI-P3 reaches about 96%, and BT.2020 around 71%. That doesn't mean the colours on the LG B6 are weak. In most films and TV series they look vivid, well saturated and simply pleasing to the eye. You only notice the difference in very bright, highly colourful scenes. Then colours lose some intensity compared with QD-OLED panels. This is due to the WOLED panel structure. In addition to the red, green and blue subpixels it also uses a white subpixel that helps boost brightness. This comes at a cost: at very high luminance some of the colour is effectively 'diluted' by the white light, so saturation of some hues can be slightly lower. Day-to-day it's not a big problem, but you can see it in the most demanding scenes.

Factory colours were checked in Filmmaker Mode, the best picture setting available to the user. TCL has been using it in its TVs for two years, and its purpose is to reproduce the image as faithfully as possible to the filmmakers' intent. On the RM7L it was indeed the best calibrated mode, though not without faults. The biggest issue was the white balance. An excess of red and blue made the image shift slightly toward pink tones. This was visible in both SDR and HDR. In addition, the brightness response was slightly boosted, so the picture looked a little brighter but at the same time less contrasty than it should.

We tested the LG B6 in Filmmaker Mode, the best picture setting available straight out of the box. ISF modes give very similar results, but in our tests we always stick to Filmmaker Mode for better comparison with other TVs. Each of them is a far better starting point than Vivid or Eco, where the picture is heavily boosted and noticeably less natural. For SDR content the factory settings perform really well. Colour errors are small, gamma behaves correctly, and the picture looks natural during regular viewing and does not seem overly enhanced.

It's a bit worse with HDR. Once you start playing that kind of content it's quickly apparent the white balance isn't perfectly set. Too much blue and red makes the image take on a slightly pink tint. Colour gamut measurements and the ColorChecker confirm this, with samples clearly shifting in that direction. It's not a defect that completely ruins the picture, but you can notice it with HDR films. So anyone who wants the most faithful image should consider calibration, which we cover later in the review.

Thanks to a fairly extensive calibration menu we managed to correct the vast majority of the issues described earlier. The biggest change was the white balance. After calibration it looks very good, so the image has lost its pinkish tint and become much more neutral. The luminance response has also improved. Both the SDR gamma and the HDR EOTF curve are now much closer to the reference values. The picture is no longer unnecessarily bright, and darker parts look more natural and have greater depth. Better luminance accuracy has also affected the colours, which after calibration are noticeably more accurate. Not everything could be set perfectly though. In HDR material the RM7L still interprets part of the signal in its own way and doesn’t always stick exactly to the reference curve. You can see this mainly in some darker scenes, where the TV can either slightly lift the shadows or darken them completely. That’s where the earlier impression of a slightly brightened, less contrasty image came from. Even so, the calibration delivers a very good result here. It removes the most visible errors and, above all, makes the picture much closer to how it should look.

During calibration we focused mainly on HDR material, because that’s where the factory settings needed the most correction. We didn’t neglect SDR, though. After tuning it was brought almost to perfection. Colours are very accurate and brightness is controlled as it should be. The biggest change in HDR came from improving the white balance. After removing excess red and blue the pinkish tint disappeared and the image became much more natural. Skin tones, whites and all colours that had previously leaned towards pink improved. After calibration most errors fell below Delta E 2-3, the threshold at which an average viewer stops noticing differences with the naked eye. So the LG B6 can produce a very accurate picture, especially for the manufacturer’s entry-level OLED model.

Upscaling and digital image processing are not the RM7L’s strong points. TCL has used a MediaTek Pentonic 700 chipset here, labelled MT5896, which isn’t among the best processors at handling lower-quality sources. The biggest issues appear with heavily compressed content from YouTube or regular broadcast TV. The processor can’t effectively hide posterisation and the characteristic banding between shades. The feature meant to smooth these issues does little to help and can also interfere with the picture too much, smoothing faces and fine textures, for example. For that reason it’s best not to use it.

Plain upscaling to 4K looks better. Lower-quality sources are reasonably sharp and retain a sufficient amount of detail. It’s not on a par with the best processors on the market, but for everyday viewing the result is perfectly acceptable.

LG B6 copes very well with lower-quality material. Much of that is down to effective digital image processing, which can mask some source imperfections without excessively smoothing the whole scene. The "Smooth Gradation" feature proves particularly useful. It lets you noticeably reduce posterization mentioned earlier, especially in dark parts of the image. The safest choice is to set it to Low or Medium. The feature still effectively smooths out harsh tonal transitions, but doesn't yet interfere too much with fine details. Die-hard purists can of course leave it off. Upscaling to 4K also performs very well. Full HD and 720p content retain a fair amount of detail, and the image is neither overly sharpened nor heavily blurred. Some limitations are only noticeable with very poor sources below 720p, where the smallest text and fine elements aren't always perfectly sharp, but this is true for almost every other TV on the market.

The RM7L uses a 144 Hz VA panel, so right from the start it's well prepared for sports, games and other dynamic content. The high refresh rate also gives the motion interpolation more room to work, so it can generate additional frames. On the RM7L it performs well and, when set correctly, can noticeably improve motion smoothness without producing an excessive soap opera effect.

One of the biggest advantages of OLED panels is their very fast pixel response time. That keeps the picture sharp and prevents visible smearing that often appears on LCD TVs. It does have a downside, though. During slow camera pans motion can look a bit choppier than on LCD screens, where the slower panel naturally masks some of that effect. Fortunately, on the LG B6 this is easy to tame with TruMotion. With the motion smoothing set correctly you can get smoother motion without giving the picture an exaggerated soap-opera effect.

When it comes to gamer-focused features, there's almost nothing but praise for the RM7L. The TV supports ALLM, VRR, Dolby Vision Gaming and works correctly with HGiG, so it's hard to point to any major gaps in that area. In practice that means automatic switching to a low-latency mode, smoother motion with variable frame rates and accurate brightness reproduction in HDR games. There's also a handy Game Bar. From it you can quickly check the frame rate, VRR status, signal format and aspect ratio, and change key settings without leaving the game. TCL has added a few extra options too, such as an on-screen reticle and brightening of dark areas, which can be useful in some titles. The biggest downside comes from using the Pentonic 700 processor. Only two of the four HDMI ports support the full HDMI 2.1 standard. With a single console that won't be a big issue, but if you hook up two consoles and a PC you might run out of ports, especially since one of those ports may also be needed for eARC and a soundbar.

LG OLED B6 has plenty going for gamers; it's a complete base for the PS5, Xbox Series X/S or a solid PC. It comes with four full-size HDMI 2.1 ports with 48 Gb/s bandwidth, so you can forget about annoying cable swapping when you want to connect several newer devices at once. We get a full package of sync technologies, from classic VRR to G-Sync and FreeSync. The panel effortlessly syncs its refresh rate to the frame pacing produced by your console or graphics card. Of course ALLM is present: the B6 automatically recognises when a game is running and immediately cuts latency to a minimum. HDR support is also excellent. The TV supports Dolby Vision, and a correctly implemented HGiG means that after an initial calibration in the console settings the picture won't suffer from blown-out whites or lost detail in bright areas. The icing on the cake is the Game Bar. Instead of digging through the full menu mid-game, a single click lets you correct shadow visibility, tweak chosen parameters or simply check the display's current mode. All of this makes the LG B6 a great choice for gamers.