LG C8 vs C9 Review (OLED77C8PUA vs OLED77C9PUB ; OLED65C8PUA vs OLED65C9PUA; OLED55C8PUA vs OLED55C9PUA)
The main LG C9 vs C8 difference is arguably the inclusion of HDMI 2.1 ports on the LG C9. That being said, there is also a difference in the AI capabilities on the LG C9 vs C8 since Artificial Intelligence is used not only for the Smart TV system (e.g. providing recommendations and natural language processing for voice queries) but also for optimizing the picture and sound on the LG C9 thanks to features such as AI Picture, AI Brightness, and AI sound. Besides the automatic adjustments, the LG C9 has more manual settings in comparison to the LG C8, such for Smooth Gradation (which is independent from the MPEG Noise Reduction), Peak Brightness (available in the user menu as opposed to service menu like on the LG C8), and 22-point white balance controls.
HDMI 2.1 (4K HFR, eARC, ALLM, VRR)
The inclusion of HDMI 2.1 ports on the LG C9 leads to this year’s OLED TV being able to accept 4K HFR (High Frame Rate) signal (e.g. 120fps) via HDMI. The LG C8 lacks that ability due to the limited bandwidth of its HDMI 2.0 ports. Both the LG C9 and C8, however, support 4K HFR via USB and streaming because they have HEVC decoder conforming to the Main10 profile at level 5.2. Even though the LG C8 supports Dolby Atmos pass-through via HDMI ARC (Audio Return Channel), the bandwidth limitation of the HDMI 2.0 constraints it to only Dolby Digital Plus encoded Atmos streams. The HDMI 2.1 inputs on the LG C9, on the other hand, have enough bandwidth to pass-through Dolby Atmos that is encoded in Dolby TrueHD (which is a lossless codec), meaning that the LG C9 supports eARC (enhanced Audio Return Channel) on one of its HDMI ports. The LG C9 has some new gaming-related features, also thanks to the HDMI 2.1 ports. For example, the LG C9 supports VRR (variable refresh rate) in order to prevent screen tearing when you play games but it’s not compatible with FreeSync, though. Once you launch a game on a compatible console, the LG C9 is able to automatically switch to game mode, or the so-called ALLM (Auto Low Latency Mode) in terms of the HDMI 2.1 features, provided you have enabled Instant Game Response in the menu settings.
Alpha 9 processor (second generation); AI Picture
The second generation Alpha 9 chip brings a number of AI-related features to the LG C9. For example, there is an AI Picture menu option for automatically optimizing the image. It does so by analyzing the quality of source, and identifying issues such as image block noise, banding, jagged edges, and blurred details. Then, based on above findings, an appropriate AI-generated algorithm is used so that an optimal noise reduction, sharpness enhancement, and detail improvement can be achieved. If you don’t wish to rely on automatic adjustments for noise reduction and banding removal, you can use the LG C9’s manual controls instead, which have their separate menu entries on LG C9, rather then being combined under a single setting as on the LG C8.
Separate controls for MPEG Noise Reduction and Smooth Gradation
There is no change in the total number of steps used for noise reduction on the second generation Alpha 9 processor (found on the LG C9) in comparison to the first generation Alpha 9 chip (used by the LG C8) since both processors rely on a quad-step process involving the application of decontouring filter in two passes, in addition to compression artifacts removal (also done in two passes). That being said, the two filters are no longer applied simultaneously on the Alpha 9 Gen 2 processor. The C9 is therefore able to remove in-source posterization artifacts without obfuscating fine details in high quality sources because the smooth gradation is controlled independently from the MPEG Noise reduction, unlike on the C8 which lacks the Smooth Gradation menu option.
Control over Peak Brightness (white subpixel boosting)
The LG C9 allows you to adjust the white subpixel boosting via the user menu, rather than going through the service menu like on the LG C8. The Peak Brightness can be set for SDR and HDR. The default values are “Off” for SDR, and “High” for HDR, meaning there is no change in comparison to the last year’s LG C8, except for the aforementioned ability to adjust this white subpixel behavior via the user menu on the LG C9. Even though the boosting of the white subpixel causes color desaturation (since red, green, and blue primary colors are being diluted by the unfiltered white light of the LG W-OLED TVs 4-th subpixel), it should be said that it’s limited to the highlights region only (i.e. above 300 cd/m²) due to the way OLED TVs with Alpha 9 chip (both generations) send RGB data to the panel, which allows for pixel level control of the white boosting (and where the color distortion occurs, respectively). Having the ability to shift the color distortion to the highlights, the LG C8 and C9 no longer need to apply global saturation boost, which may interfere with the color volume at mid and low luminance levels. By setting the Peak Brightness to “Off” for HDR content, you can eliminate color distortion altogether (at the expense of lower peak brightness, though). If you use the Manual HDR tone curve in the CalMAN software (sold separately), then you can adjust the roll-off point in the PQ EOTF tracking relative to the peak brightness of your TV, so that there is still room for tone-mapping specular highlights (although mid-tones (and even shadows) in that case will be highly compressed). Alternatively, you can hard-clip any highlights above the peak brightness of your TV. Given that there are also Low and Medium settings for the Peak Brightness, you should be able to find the right balance between the luminance output and color saturation in highlights, even without using the Manual HDR tone curve.
AutoCal: Manual HDR tone curve (via CalMAN software); iTPG (Integrated Test Pattern Generator) on the LG C9
The CalMAN software (sold separately) is able to directly access 1D and 3D LUT (Look-up Tables) on both LG C9 and C8. Considering that the LG C9 has built-in pattern generator (that operates in RGB color space and has 10-bit precision), you’ll only need spectrometer in order to perform auto-calibration. The LG C8, on the other hand, doesn’t have the ability to generate test patterns, so you have to separately purchase an external pattern generator if you wish to auto-calibrate using the CalMAN software. There is no difference in the size of the look-up tables on the LG C9 vs C8, though, meaning that both TVs have comparable color accuracy thanks to the 3D LUTs being 33x33x33 in size, meaning there are 35,937 color data points (not all of them are measured). Another new feature for the LG C9 is the ability to choose the exact roll-off point (relative to the measured peak brightness of your TV) in the CalMAN software. This can be done for up to three mastering peaks (e.g. 1,000 cd/m²; 4,000 cd/m²; 10,000 cd/m²), which allows you to tailor the tone-mapping of HDR TV series and movies mastered to either 1,000 nits or 4,000 nits, as well as HDR games (with 10,000-nit peak brightness), exactly to your preference. If you’re not satisfied with the results of the auto-calibration, the LG C9 allows you to reset picture modes individually, rather than doing a global factory reset like on the LG C8.
More granular near-black adjustments (for manual calibration)
Even though there is no change in the 1D LUTs (Look-up Tables) on the LG C8 vs C9 since they both use 1024-point 1D LUTs with 15-bit precision, in addition to having identical bit precision of the data they output to the panel (so the near-black rendition is on par between them), it should be said that the LG C9 has 22-point white balance controls, including for 2.5% and 7.5% stimulus, meaning that, in the event of manual calibration, you have more control over adjusting the near-black gamma tracking.
AI Brightness (Automatic adjustment of HDR tone-mapping based on ambient light)
Besides the aforementioned white subpixel boosting, the LG C9 has more ways to show brighter image in HDR, especially in a high ambient light environment. It’s thanks to the AI Brightness which uses readings from the ambient light sensor in order to adjust the PQ (Perceptual Quantizer) EOTF tracking accordingly. The AI Brightness can also be used with Dolby Vision content, which is noteworthy since this format uses dynamic metadata, meaning that is already optimized on a scene-by-scene, or even frame-by-frame basis, so the LG Dynamic Tone Mapping cannot be used with Dolby Vision for the purpose of achieving brighter image. When it comes to HDR10 content, though, you can use Dynamic Tone Mapping in order to avoid the dynamic range being unnecessarily compressed during scenes without highlights (because of the static metadata that doesn’t change for the entire content duration).
AI Sound; AI Sound tuning
Although there is no change in the speaker configuration on the LG C9 vs C8 since they both use 2.2-channel system with a total audio power output of 40 Watts, the LG C9 is able to up-mix stereo sources to 5.1-channel virtual surround sound, thanks to the AI Sound technology provided by the second generation Alpha 9 processor. The AI Sound is also able to optimize sound based on the type of content that is playing on the TV. Additionally, the AI Sound tuning uses the built-in microphone in the Magic Remote to equalize the TV speakers but the LG C8 also has the ability to perform acoustic room correction. The LG C9 is WiSA Ready, meaning that you stream audio to compatible wireless speakers but a dongle is required (sold separately). The LG C8 and C9 have a built-in decoder for Dolby Atmos but there are no up-firing speakers so, if you choose Dolby Atmos soundtracks to be decoded for playback directly by the TV (instead of bitstreaming to a compatible receiver or soundbar), the height channels are not going to be optimally reproduced.
Pricing & Availability
Check availability and pricing on Amazon.com for the LG C9 and LG C8 (affiliate links to the 65-inch class TVs from each series. As an Amazon Associate I earn from qualifying purchases.)
