In terms of pure specs, the TCL QM9K is a 4K QLED mini-LED TV with a 144Hz native refresh rate and support for high dynamic range (HDR) content in Dolby Vision, HDR10, HDR10+, and hybrid log gamma (HLG). It has Wi-Fi 6, Bluetooth 5.4, and an ATSC 3.0 tuner for 1080p and 4K over-the-air broadcasts.
The QM9K technically isn’t the brightest TV I’ve ever tested, but it is the brightest I’ve ever evaluated in PC Labs. The only one that beats it is the Hisense 116UX, a 116-inch TV with a very new RGB LED backlight system and a $25,000 price tag, a model I had to test offsite because it was too large to fit into the lab. Among non-massive, non-five-digit models, the QM9K definitely puts out the most light.
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Using a Klein K-10A colorimeter, a Murideo SIX-G signal generator, and Portrait Displays’ Calman software, I tested the QM9K with multiple signal types and in multiple picture modes to determine the brightest settings while maintaining color accuracy. That turned out to be HDR Filmmaker mode (Standard and Vivid modes will get higher numbers, but those colors will be horribly skewed) with an HDR10 signal. I measured a peak luminance of 769 nits with a full-screen white field, 3,330 nits with an 18% white field, and 4,296 nits with a 10% white field. I use the 18% white field measurement to compare all TVs across the board for consistency, but the 10% field number is a useful reference for certain TVs that can brighten considerably under those conditions (usually OLED TVs, but sometimes high-end mini-LED TVs).
The QM9K is just a little bit dimmer with a full-screen white field than the previous record-holder, the Hisense U8QG (845 nits), but it edges out that model with an 18% white field (3,200 nits) and downright eclipses it with a 10% field (3,404 nits). The TCL QM8K also comes close, with 720 nits of peak brightness with a full-screen white field, 2,849 nits with an 18% field, and 3,138 nits with a 10% field. That may sound like a big step down, but even the QM8K falls on the high end of the brightness scale among TVs. The Hisense 116UX still beats all with 1,143 nits on a full-screen white field, 4,012 nits on an 18% field, and 5,889 nits on a 10% white field, but again, it’s gigantic and crazy expensive.
(Credit: PCMag)
Color performance is generally very good, with one common quibble and one small but unusual quirk. The above charts show the QM9K’s color range in Filmmaker mode with SDR and HDR10 signals, and in Dolby Vision Bright mode with a Dolby Vision signal. The SDR signal is compared against Rec.709 broadcast standards, while the two HDR signals are compared against the wider DCI-P3 digital cinema color space. SDR colors are nearly perfect, HDR10 colors are very wide but see magentas drifting toward red, and Dolby Vision colors are more balanced but don’t cover as wide a range. The Hisense U8QG’s color range isn’t quite as wide as the QM9K’s with an HDR10 signal, but its magentas are much more accurate, and its Dolby Vision performance comes closer to covering the full DCI-P3 space.
(Credit: PCMag)
A notable quirk is that the white balance shifts as the screen gets brighter with a smaller field. When measuring peak brightness, I noticed that the white of the 18% and 10% white fields looked much cooler than the full-screen white field. I use full-screen fields when testing color performance on TVs, but I ran additional tests with 18% fields to see just how much of a difference the backlight brightness was making. Sure enough, colors pull slightly cooler as the TV emits more light. However, even with that amount of drift, white balance stayed close to accurate (within the center box on the chart), and other colors didn’t significantly tint. So, while there is some variation, you likely won’t notice it unless you’re staring at flat rectangles in a dark room across multiple picture modes as I do for testing TVs.
BBC’s Planet Earth II is bright and vibrant on the QM9K. In the “Island” episode, greens and blues look well-saturated and natural, and sunlight shining through trees can be almost blinding. The mini-LED backlight’s control ensures that dark fur in shade still appears dark, even when the rest of the frame is brightly lit.
The party scenes in The Great Gatsby show off the QM9K’s contrast even better. In HDR10 Filmmaker mode, the whites of lights, shirts, and balloons stand out nicely, while black suit jackets still appear very dark, yet retain fine details like their cuts and textures. HDR10 Movie mode makes the white highlights downright blazing, to the point they’re at times distractingly bright. The black suits manage to look black, rather than gray, but they don’t appear nearly as dark in this mode.
(Credit: Will Greenwald)
Despite its extreme brightness, the QM9K manages to avoid significant clipping (the effect where the brightest parts of the picture lose detail and become homogenous fields). On the Spears & Munsil Ultra HD benchmark disc, the snowy peaks of a mountain range in a time-lapse shot, transitioning from early morning to midday, appear bright while still retaining the texture of their slopes. Wintery shots also capture the edges and textures of white clouds and snow against a white sky.
The benchmark disc has several clips of bright, colorful objects against completely black backgrounds, which serves as a torture test for LED TVs in terms of light bloom. Here, the QM9K shows a slight glow of haze creeping from the edges into the blackness, but it’s minimal when viewed head-on. The bloom becomes a more apparent aura, and colors slightly desaturate if you look at the screen from a side angle, but even then the picture is very watchable. The light bloom is only really distracting in these particular torture test shots and probably won’t be noticeable in the majority of normal movies, TV shows, and other content.
