LG 55 B4 vs Sony X75WL

The HDR brightness performance of the LG B4 is impressive, even though it doesn't surpass 1000 nits. Its luminance stability is consistently strong across various scenarios, delivering a reliable viewing experience. The only instance where the TV shows slight weakness is in scenes with large areas of bright white, which has long been a challenge for OLED technology. However, perfect contrast, deep blacks, and excellent brightness ensure a fully immersive HDR experience. Furthermore, the TV’s remarkable 99% coverage of the DCI-P3 colour gamut enhances its colour vibrancy, making images appear rich and visually striking. This level of colour accuracy and brightness balance firmly places the LG B4 among the top choices for HDR content.

The luminance chart for the Sony X75WL revealed a peak brightness of just 350 nits, which is underwhelming for an HDR-capable display. This limited brightness means that HDR scenes lack the depth and impactful highlights expected for immersive viewing. Additionally, the subpar coverage of the DCI-P3 colour gamut results in a less vibrant colour representation, negatively impacting the overall quality of HDR content. The combination of insufficient brightness and poor colour gamut coverage significantly diminishes the intended HDR effect, making this model a less compelling choice for those prioritising HDR performance.

The best factory preset offered by LG B4 is the "Filmmaker" mode, which we used throughout our testing. Straight out of the box, the TV delivered fairly accurate colour reproduction. However, the most significant issue in both SDR and HDR content was the white balance. In SDR, there was a noticeable red dominance, giving the image a distinct yellow tint, particularly evident in skin tones and whites. In HDR, this red hue persisted, but the lack of blue also introduced a greenish tint in certain scenes. Additionally, we observed some inconsistencies in grayscale and colour accuracy. Despite these shortcomings, the overall picture quality was still solid for most viewing scenarios.

Colour reproduction tests on the X75WL model, conducted in movie mode, reveal strengths and weaknesses. While movie mode offers some of the best image settings, it is not flawless. One of the most significant issues with the X75WL is the white balance, particularly for HD and 4K HDR content, where a blue hue dominates the image. This results in a noticeably cold tone throughout. The colour checker confirms these discrepancies, showing a clear shift towards cooler shades.

Regarding brightness, the contrast gamma level is generally acceptable, but the EOTF curve presents more challenges. There are noticeable problems with maintaining consistent brightness, with the image sometimes appearing too washed out or too dim. These issues affect the overall visual experience and hinder the accurate perception of content.

LG B4 has long been known for offering advanced calibration tools, and it remains one of the few manufacturers that allows such in-depth image adjustments. Thanks to these tools, we calibrated the device to an exceptional standard. The result was incredibly low deltaE errors, considered at a reference level. Both SDR and HDR content now display exactly as the filmmaker intended. This level of precision is one of the reasons LG TVs are frequently used as preview monitors in graphic design and post-production studios.

The X75WL is one of those cases where image calibration may not lead to a dramatic transformation, but it does offer a notable improvement in colour perception. The white balance for HD and 4K content, has been significantly enhanced, eliminating the strong dominance of cooler tones. The gamma chart also appears more stable, resulting in better image quality overall. However, the main issue remains the EOTF curve, which controls brightness in 4K content. Due to the technological limitations of the television (such as the IPS panel and the absence of local dimming), a significant improvement is difficult to achieve, as the model’s capabilities are constrained. Despite these limitations, the tonality of the image has been substantially improved.

In this section, we will revisit the smooth transition function while also examining how the TV handles lower-quality content. As we’ve found, the setting responsible for smooth gradation is generally effective, though it does have its drawbacks. While the function works well in SDR content, it becomes less useful in HDR content. Even at the lowest setting, it can blur important details, so we advise against using it in such cases.

The image scaling on the LG B4 is assessed moderately positively. While there is no noticeable edge doubling, the image tends to be somewhat "soft." This can be adjusted by tweaking the sharpness slider to improve the clarity.

The X75WL struggles with low-quality tonal transitions. The lack of any function to improve tonal gradation results in noticeable imperfections in colour transitions, which detracts from the overall image quality. However, the digital processing is commendable, with the image displayed without overscan, and relatively sharp presentation. This added sharpness may appeal to some users, though it does not compensate for the tonal transition issues.

The maximum refresh rate on the LG B4 is 120 Hz, the bare minimum for those requiring high image fluidity. The manufacturer has equipped the TV with a multi-stage motion smoother called "TruMotion." This feature is split into two sliders: one controls the sharpness of moving images (De-Blur) and the other adjusts judder (De-Judder). Both sliders can be set between 0 and 10, with each level affecting the smoothness, so users can easily find their preferred setting.

The LG OLED B4 panel boasts an impressive average response time of 0.1 ms (based on our measurements), delivering an exceptionally clear image that surpasses the capabilities of LCD TVs, which often have response times of several milliseconds. This is particularly noticeable in the "UFO Test" images, where no trailing blur is visible behind moving objects.

The X75WL features a 60 Hz panel, making it more suited for movie-watching than high-speed gaming. It is equipped with a motion smoother function called Motionflow, which allows users to adjust picture fluidity on a 10-point scale. This function adds intermediate frames, improving motion smoothness and creating a more cinematic effect by reducing choppiness. Additionally, the clarity adjustment helps reduce motion blur, making it particularly beneficial for fast-paced scenes like sports or dynamic action sequences in films. With these settings, users can fine-tune the fluidity and sharpness of motion to their preferences.

The LG B4 has four full HDMI 2.1 ports, each providing 48Gbps bandwidth. This ensures smooth activation of all relevant features without issues, making the television highly suitable for gaming. With its low input lag and extensive functionality, including well-implemented HGIG mode and Dolby Vision gaming with low latency, the B4 is a strong contender for gamers who demand high quality.

A standout feature is GameBar, which allows for on-the-fly adjustments without interrupting gameplay, as well as image adaptations for those with visual impairments. Another key point is that when VRR technology is enabled, the television maintains its contrast, thanks to the OLED panel's structure, though slight flickering in grey shades is to be expected.

In conclusion, the LG B4 is an ideal choice for gamers, seamlessly combining high performance with excellent gaming features. Its 120Hz panel and HDMI 2.1 ports make it a standout option for those seeking top-tier gaming experiences.

The X75WL is not the best television for gamers, as it lacks some key features that more demanding users expect. While it includes the Auto Low Latency Mode (ALLM) and a basic Game Bar, these are not sufficient for a truly immersive gaming experience. In this price range, features like VRR (Variable Refresh Rate) and a 120 Hz refresh rate—at least in Full HD—have become standard, but unfortunately, these are missing in the X75WL. This is a significant drawback for Sony, as the competition offers more advanced gaming features at a similar price.