LG OLED77CX Review

LG OLED77CX Review: Monster Screen Deserves to Live as the Heart of Your Home Theatre

We’re almost a year into COVID lockdown, and beyond the travel and the friends I can’t spent time with and the restaurant foods I crave, above almost everything I desperately miss the theatrical experience. From the tiniest festival screen to the largest IMAX cathedral, the secular worship of images and sound at a cinema with a receptive and respectful crowd is simply impossible to replicate at home, no matter how impressive your setup.

As more and more festivals have gone virtual, and opportunities to screen even blockbusters have been relegated to home viewing, the need (and desire) for professional reviews such as myself to replicate as best we can the impact of theatrical presentation has never been more acute. While budgetary limitations are an obvious factor, I remain aghast at those that have traded in a screen hundreds of feet across for a tiny laptop screen or a bargain basement LCD set on whatever picture default mode was meant to highlight the set in a big box store that still adjudicate the visual impact of these titles.

For half a year I have had the opportunity to have LG’s OLED77CX at the heart of my system. My home theatre has been built up over many decades, starting with CRT and moving through rear projection, Plasma and finally OLED in an attempt to get as close to cinephilic glory as possible. With this latest model from LG, I’m as close as I’ve ever been to get the picture that the filmmakers intended replicated in my home environment.


All 2020 models of the LG OLEDs run the same panel, with the differences between the CX and GX solely a matter of differing sound output and cosmetic look of the chassis. For those of us that mute the built-in audio the difference is of course superfluous, making the CX the obvious choice.

Both sets use the 3rd generation of LG’s Alpha-9 AI Processor, the brain that give the panel its punch. It may seem odd that the caliber of televisions are so significantly tied to the central processor, but the fact remains that these sets are enormously complex image processing units, with the screen a relatively small delineating factor in terms of picture quality. The fact of the matter is that the screen construction has remained relatively static for the last several years, with the only major improvements being software and improvements in this image processor. Furthermore, since every major manufacturer sources their panels from LG Display, what sets the LG Electronics sets apart from, say, Sony or Visio comes down to the implementation more than it does the most obvious part of the set.

The TV is 67.83″ x 39.09″ (1723mm x 993mm), and stands a mere 2.18” (55.3mm) at its thickest point. Years after purchasing my first model of this technology it remains almost like science fiction, where the implausibly thin screen that runs the majority of the set feels as if it could never do the magic trick of presenting these images.

Weighing around 60lbs (27kg), the set easily is accommodated on even moderately-priced wall mounts. In my case I have it on an articulated stand that steps out from the wall by several feet, putting the front of the screen in line with the front of my B&W MTM1-D2 center channel speaker. The result is a pleasantly monolithic hovering effect, appropriately ominous with the lights on but perfect when dimmed.

Size Matters

At this time when theatres are closed to most audiences, the ability to recreate at least some of the experience at home has never been easier. With access to 4K discs running well over 100mb/s and lossless ATMOS object-based surround mixes, we are living in a golden age for home media reproduction.

With higher resolution comes the ability to sit closer to the set in order to provide the right kind of theatrical impact and benefit from the picture quality improvements. The ideal distance from a 77” 4k set is between 6 and 9 feet away, which is often far closer than people raised on CRT are used to. Back then the closer you were even to a 20” set resulted in seeing the scanlines and interference patterns exposed, while with a technology like 4K OLED you’re gifted with an image that from a few feet away renders without any native display issues. In fact, walking right up to the screen and putting it inches away from your face, as people do all the time with the OLEDs on their mobile devices, still makes the pixel structure difficult to separate from the image being presented.

It was this increase in size, and better application of HDR, that led me to upgrade from my beloved 2016 model that was a ‘mere’ 65”diagonal.

The Technology

OLED is by its nature a self-emissive display technology. Like old-school CRT and Plasma displays, this allows for sections of the screen to bit illuminated while neighbouring sections of the screen are left dark. The clearest test for this is a starfield (found, like many exceptional tests, on the Spears & Munsil discs). On a conventional LCD screen a consistent backlight means that the black is actually a soft grey, where the bright points of the stars are set against a raised black level. Note that this is also the same case in projectors, though the choice of screen material does wonders to ameliorate that. More advanced LCD screens allows certain sections to be turned on or off, meaning that the only portion that is illuminated is where there’s content, so a bright portion on one section has backlight while the rest can in fact be fairly close to pure black. New micro-LED backlit technology coming in 2021 is increasing these illumination zones to the hundreds, greatly increasing the capability of LCD to deliver a better picture.

That said, this is still paltry compared to OLED, where since each pixel is able to self-illuminate it’s the equivalent of millions of zones. Another test on the S&M disc, a 1 on, 1 off pattern where every other pixel is illuminated, is presented perfectly on a set like LG’s OLED77CX, while on any LCD of even the most professional model will fail in its attempts to recreate the pattern on screen.

Fundamentally, then, OLED does a better job with black level presentation, full stop. While it lacks the crazy intensity of a blasted 4000+ nit LCD monitor, the end result is a picture whose relative contrast appearance (from the darkest to the lightest elements) is significantly better than LCD. Even more impressive, by being pixel accurate the sharpness of the presentation is equally improved, making a 4K OLED often significantly more impressive picture wise than even an 8K LCD presentation (meaning, of course, that 8K OLED is all the more remarkable, even as the costs are exorbitant at this time).

What’s Added

With the 2020 models LG has continued its incremental improvements in image processing, especially regarding High Dynamic Range content. Thanks to players like the Oppo 203, where one can easily set the priority for processing to the TV set rather than on the playback device, the image caliber is often nothing short of astonishing.

For all the talk of resolution improvement from regular HD to 4K, by far the biggest changed has been the improvements moving from standard dynamic range (SDR) to HDR. By adding millions of more colours to palate the result is not only far more accurate to the source material but equally a substantial jump towards replicating the theatrical experience. The expansion of the range between the brightest and darkest elements is one factor, but an even more impressive aspect is how it allows for far more subtle gradation within similar coloured elements. Throw in a disc as breathtaking as Sony’s Lawrence of Arabia and immediately notice how the particles of sand and subtle shifts in colour give the scenes in the desert even more impact. Sure, glossy modern productions shot on HDR rigs are significantly better compared to SDR presentations, but it’s these presentations of classics shot on film that often have the biggest jump in quality.

This year saw the addition of Filmmaker mode, an automatic feature that essentially presents for relevant content as close to a calibrated picture mode as possible. What’s unique about OLED is that even if you turn off all the consumer-friendly processing that makes things look waxy and more like a video game the resulting picture continues to improve, where on LCD the more you turn off you get to a point where the image start to suffer.

There are numerous additional elements such that use Artificial Intelligence to determine the type of programme being watched and tune the TV accordingly, making sports programs more vibrant while dialing things back down for dark, cinematic imagery. For many these jargony features such as “Face Enhancement”, “Quad Step Noise Reduction” and “Frequence-based Sharpness Enhancers” will be a boon, but for this reviewer most of these elements are useless and immediately disabled.

Within a month of having the set, and after some firmware stabilization, I had the unit professionally ISF/THX calibrated, ensuring that regular SDR, HDR and Dolby Vision signals looked as accurate as possible on all inputs. This for the most part belayed the need to implement any of the automatic, real-time processing and instead have the television display the image according to professionally established benchmarks. While Filmmaker mode and other enhancements go a long way compared to past sets in creating a look as close as possible to standard, it remains the case that given the variance between panels within even the same model line and year, there is still a required individual tuning to get the most out of one’s respective unit.

The persistence of image retention

Because the pixels of an OLED decay over a period of time, constant illumination of one part of the screen can result in what’s often misleadingly called “burn-in”. In order to ameliorate these artifacts the latest sets from LG incorporate numerous technologies, from pixel orbiting (to shift the image around in a way impossible to see by the naked eye) and to automatically dim logos and other static on-screen elements that are the highest contributor to potential image retention. There have been numerous torture tests using late model OLEDs that have demonstrated conclusively that with regular viewing habits there’s almost no fear of this issue cropping up, especially for those using the set primarily for TV and movie watching with occasional gaming. Undefeatable automatic brightness limiters assist in extending the life of these individual pixels, and as someone who have lived with the 2016 model with over 10,000 hours on it I can attest that even an avid watcher of Cable news and films with letterboxing have never caused any image persistence.

While LCDs can be left on a static screen near indefinitely, it’s true that the very nature of OLED technology that gives it its capacity to express perfect blacks without distortion, glare or hazing does have this specific drawback. The excellent news is that with the 2020 models the built-in elements to prevent such occurrence are for the most part invisible to even the most critical eye, allowing viewers to simply sit back and view the truly remarkable images that this unit can present.

What got left behind

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As one of the few fans of 3D technology I continue to decry the addition of useless motion interpolation added to contemporary set while eschewing the capacity of stereoscopic playback. On my 65E6P I was able to play 3D Blu-rays with 1080p resolution per-eye, better in some facets than even theatrical 3D. Using Real-D passive glasses, the screen essentially used the 4K resolution to split ever other line in lenticular fashion, with half for one eye and half for the other. The result is often astonishing, particularly for titles like Gravity, Mad Max: Fury Road, and even exceptional post-converts like Jurassic Park and Top Gun.

Beside consumer disinterest in 3D playback, the 4K disc alliance actually dropped support for the format in the new generation of discs, providing a further death knell for fans of what for many films are the definitive versions. This is a classic example where the technology is actually getting worse, and except for projectors there’s really no way in 2021 to buy a set at any price that allows the playback of hundreds of 3D titles.

LG also dropped for 2020 DTS playback via its internal apps. This means, for example, if you have a DTS file on a server (even an audio-only DTS file) it will not bitstream properly over HDMI-ARC/eARC to your receiver, or playback audio at all on your TV speakers. Since I use other devices for media playback this isn’t a big issue, though it’s certainly a notable one.

Compared to the 2019 panels they also dropped slightly the HDMI 2.1 capability, downgrading from 48gb/s to 40gb/s. While this is only of interest to gamers who are putting high-end cards into this set to use as a monitor, and the fact that it’s a 10bit set and therefore can’t actually display the 48gb/s content anyway, this is one of those spec-hunting bits of nonsense that does not really affect anyone, including the most vocal about such issues.

Real word usage

As of the writing of this review I’ve got 1030 hours on my set, a somewhat astonishing 42 days worth of viewing since receiving it in late August 2020. The firmware as of writing is 03.21.16 which dropped a few weeks ago and managed  along with previous iterative improvements after all this time to solve nearly every issue I’ve had with the set until this point.

The very first 4K UHD film I played all the way through, The Deer Hunter, is a notoriously dark and murky presentation and exactly the kind of torture test for home viewing. On my first viewing, pre-calibration, I was distressed about a couple issues that spoiled the presentation. First of all, near-black imagery was crushed, meaning that everything below a certain point just devolved into pure black as if you were watching a dirty print. Secondly, after the scenes in the prison camps that then cut back to life back in the U.S. there was a sudden change in luminance after a half-minute, resulting in a highly distracting shift between the darkened and light elements.

For the first element I tested the set’s capacities using the S&M disc, surprised to find how much I had to crank the settings to have a pleasing black level. I left that evening to attend a drive-in presentation (which itself had near comical levels of black-crush problems), only to return and find after leaving the set for a while things to have reset themselves.

This felt a little bit like a Mandela effect, where suddenly everything that I had believed an hour ago had shifted without me knowing. What seems to have occurred is that a compensation cycle finally ran when the TV had some time without me playing anything on it. It’s one of those strange technology things where leaving it plugged into the wall, but powered off for several hours, allowing its built-in tools to recheck the voltages of each pixel and ensure that everything was nominal. One this was done everything performed for the most part as expected.

As for the dimming after dark scenes that went back to bright, that seemed to be a factor that affects the 2020 models far more than my previous 2016 unit. In order to turn this off, while remaining cautious about doing something that would affect the long term life of the panel, I was forced to go into the service mode. Following advice from professional calibrators I disabled two elements under the OLED section – TPC and GSR – and that seemed to do the trick.

In the coming months there were a few other quirks with images, particularly on Dolby Vision titles. There was significant talk by many about black crushing, but what I noticed above all on my calibrated set was actually elevated black levels, resulting in digital noise that otherwise would have been buried in the pure black information. TV signals do not use the full RGB range the way that PCs do, relegating blacker-than-black and whiter-than-white signals to, ideally, to the pure white/black signal. This overhead is a result of legacy broadcast colour information, but it equally plays a major role in proper setup, ensuring that you’re setting the top and bottom levels to correspond with the appropriate range.

On one title in particular – Star Wars: Revenge of the Sith – it was easy to reproduce errors right from the opening moments on disc. When the Lucasfilm logo dissolves to black there would be a scattering of pixelated noise in the bottom right hand corner, repeated after the “A Long Time Ago….” Text appeared as well. On this title it was a minor inconvenience, of course, but in other presentations such as the Amazon Prime Small Axe stream such noise resulted in significant posterization and distraction.

It was only in the last few weeks – a half year after purchase! – that the latest firmware seems to have ameliorated these issues. The cause seems to have been an undiagnosed elevation of one of the low IRE levels in the 3D Look Up Table, essentially a bit of code that maps incoming video signal to the performance of the TV. By adjusting that one frequency response the image does get a small bit darker at near black, but exhibits far fewer issues in most programming, and completely cleaned up the errors spotted on the Star Wars disc mastering.

This entire escapade illuminates something critical when it comes to sets like this – with 77” to blast as your eyeballs, and the remarkable ability of OLED to present imagery in such an accurate way, you are going to notice issues with bad mastering on disc or bit-starvation from streaming. The myriad of post-processing capabilities on the set could of course smooth out some of these issues, but the fact remains that with such a powerful and accurate set you’re going to find issues with the sources. The Star Wars discs were clearly mastered on a LCD mastering monitor costing 10x more than my set yet due to that underlying technology is fundamentally ways less revealing that what I have in my home.

What elements still annoy?

LG OLED77CX Review

Compared to the premium remote that came with my equivalent model from 2016 the new magic remote is far more plastic-y and feels low rent for such a premium device. It’s a relatively small matter, to be sure, but the fact that you still need the remote for many of the key features given its cursor and radio frequency controlled operation (vs Infrared, which could be programmed into my main device) things are a step back.

While the latest version of the built-in LG system of apps dubbed WebOS works quickly enough there are still a few annoying quirks. First, previously one could lock the HDMI input to the selection, allowing quicker access from that bar between built-in streaming services like YouTube, Netflix, Prime or Disney+ and access to the rest of the home theatre components. As a work around I’ve programmed the numeric buttons on the remote – holding down #1 selections HDMI 2, where a few of the other numbers have been set to Over the Air channels from my roof antenna – Buffalo based commercials have to be viewed for the Superbowl, after all!

The vagaries of HDMI handshaking are hardly unique to this device, but since purchase the handshaking between my IPTV cable box, through my Marantz 8802A and the television result often in picture but no sound, requiring a “reboot” either of the pre-amp or the television. It’s a finicky thing, even with the ARC power settings disabled, but a small price to pay to have the audio return channel for the built-in apps when required.

Should I wait for 2021?

It was never intended that I spend six months living with this set, after waiting several months more for delivery due to delays thanks to the pandemic, before collecting final thoughts about the unit. The fact of the matter is that pending a number of firmware updates there were significant causes for concern. There were times when the set would simply not behave as expected, whether it was in the form of distorted picture at low-black levels or even general operations, where some of the built-in features would simply not behave as would be expected. With the latest update things finally seem to have settled and for the better, resulting in a picture image that rivals, and in many ways surpasses, any television of this size on the market.

As noted previously, the panel technology itself has been reasonably static for many years, making year-to-year improvements subtle but noticeable. For 2021 and beyond, LG is implementing a technology from their display division that was previously unique to Panasonic units, and even then only on their 65” models. Using an aluminum substrate to facilitate cooling, these enhanced panels allow the panel to be pushed to higher brightness, resulting in an even more accurate picture and enhanced HDR capabilities. For 2021 it seem that these panels will be fitted to the higher-end Gallery series, with the screen size stretched not insignificantly to 83”.

While full details on these changes are sparse, it’s clear that we’re about to get another welcome bump in OLED performance, as more and more manufacturers are realising the benefits of the display technology. It’s clear that moving forward this will result in even more powerful sets than anything from the current model year, and the differences will be far less subtle than some of the more recent updates. That said, it’s equally clear that the price of the G series will be even more of an obstacle for most consumers, though a small percentage of what only a few years ago was expected for sets of this size (a reminder that when the 2016 65” model was purchase its retail price was almost $10,000, and the 77” model back then was near impossible to secure and commanded a princely $35,000+ to buy).

It’s obvious that the 83” G1 series will be a highly coveted set, in many ways a notable improvement from what you can buy now with the CX/GX models. That said, during this time of transition the impetus to purchase one of the current year models has never been more economical. This is of course still a luxury item within the sector, and for significantly less money you can pick up a smaller set using the competing technology. Yet for those looking for the best, the 2020 CX model looks to be in that sweet spot. When the C-series implement an 83” size using the cooling substrate in a 2022 or beyond, that may well be a time to covet with even more interest, but for now, for the biggest bang for your buck, you absolutely cannot go wrong with this exceptional television set.

Final Thoughts

The LG 77OLEDCX is a remarkable piece of technology, using this panel technology to present imagery that rivals any theatrical presentation, and in some ways surpassing that lofty bar. Thanks to diligent and regular firmware updates all minor quirks seem to have been resolved, and it’s clear that this can easily be conisered a reference-caliber set. This is the ultimate television for everythign from Over-the-Air HD broadcast through to the highest bitrate UHD title. I’ve spent hours upon hours experiencing film festivals, rediscovering old classics and watching the news unfold on a screen that only few years earlier was the stuff of dreams, and thanks to its larger size, its exceptional colour fidelity and eye-popping HDR capabilities, I could not be more pleased with this latest addition to my audio/visual setup

The fact remains that if you’re serious about what you watch, and you’re able to accommodate a set of such stature in your setup, you should absolutely be considering this television for your setup. It’s a luxury item, indeed, but given the dramatic price reduction over the last few years that seems to have stabilized at this level, you’re investing in something that is significantly better than its lesser priced rivals. Right at the sweet spot between performance and affordability, the LG OLED77CX is highly recommended for those of you willing and able to make it the heart of your own home theatre.


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