Comparison TCL 55P638 55 " vs TCL 55P635 55 "

— Edge LED — side backlight of the matrix. In this case, the LEDs are distributed around the perimeter of the screen. To evenly distribute the backlight, the background of the matrix has a special reflector. An important advantage of TVs with Edge LED backlighting is the minimum thickness of the device. Among the shortcomings, one can note the presence of glare at the edges, which appear under certain conditions. Glare may be visible in scenes where dark hues predominate.

— Direct LED — rear matrix backlight. In this case, the LEDs are evenly distributed over the entire screen area. The Direct LED backlight makes the image contrast and bright at the same time. TVs with this technology have good colour reproduction. Among the shortcomings can be noted increased power consumption and increased dimensions. Additionally, such TVs have a large delay (Input lag), which is why Direct LED backlit screens are poorly suited for dynamic games.

— FALD (Full-Array Local Dimming) is a backlight technology widely used in LG TVs. A close analogue of FALD is the Direct LED backlight. The LEDs are also evenly spaced across the entire surface of the matrix, but FALD technology provides a bright, colour-rich image with high contrast. Another distinctive feature of FALD is the ability to reproduce natural blacks. When black is displayed on the screen, the LEDs are turn...ed off in groups, by sector, which allows to make black extremely saturated. Of course, the abundance of LEDs on the matrix makes the TV more massive, and at the same time heavy. The appetite for electricity in such models is above average.

— Mini LED. Screen backlight system on a substrate of reduced LEDs (hence the Mini prefix). On the same plane of the TV panel, the number of LEDs has increased several times, if we draw parallels with traditional LED systems. As a result, the canvas with Mini LED backlight has many times more local dimming zones of the picture (Local Dimming), which is necessary for the correct operation of the extended dynamic range image technology. For playing HDR content, Mini LED systems are much better than ordinary LCDs.

— Dual LED. Proprietary backlight system used in Samsung TVs. The technology involves illuminating the image on the screen with two types of LEDs: one emits light in a cold spectrum, the other in a warm one. The Dual LED enhances colour reproduction and enhances detail contrast by adapting the colour tone of the picture according to the content on the screen.

The type of coating used on the TV screen.

— Matte. Historically, the first type of coating for LCD screens, which is often found today. Screens with such a coating generally have average characteristics of brightness, saturation and colour reproduction quality, in terms of these indicators they are inferior to glossy counterparts. However, the matte coating has one important advantage: it has virtually no glare from ambient light. In some situations, this can be an important advantage — for example, if the TV is installed opposite the window. And for some users it is more pleasant to look at the screen without glare, albeit relatively dim.

— Glossy. A coating designed to improve the brightness and colour quality of the visible image compared to matte screens. The creators have managed to achieve this goal: "glossy" screens really provide rich, vibrant colours and a brighter image. The key disadvantage of such screens is the appearance of glare from ambient light on them — this can ruin the whole viewing experience. Because of this, the classic glossy coating is practically not used today, anti-glare solutions have taken its place (see below).

— Glossy (anti-glare). Modification of the glossy coating, created, as the name implies, in order to eliminate the main drawback of the classic gloss — glare from external lighting. This is not to say th...at such screens do not glare at all, but there are much less reflections on them than on ordinary glossy ones. As for the image quality, it is at least not much worse, and often even better (especially since such coatings are constantly being improved). Thanks to all this, most modern TVs of all price categories are equipped with anti-glare screens.

The maximum brightness of the image provided by the TV screen.

The image on the screen should be bright enough so that you do not have to strain your eyes unnecessarily to view it. However, too high brightness is undesirable — it will also lead to fatigue. The optimal brightness level depends on the surrounding conditions: the more intense the ambient light, the brighter the TV screen should be. So, on a sunny day, the screen may have to be “turned up” to the maximum, and in the evening, in dimmed light, a relatively dim image will be more comfortable. In addition note that large screens require higher brightness, since they are designed for a greater distance from the viewer.

Thus, the higher the number in this paragraph, the greater the margin of brightness this model has, the better it will show itself in intense ambient light. The lowest indicator sufficient for more or less comfortable viewing in any conditions is 300 cd/m² for models with a diagonal of up to 32", 400 cd/m² for models in the range of 32 – 55" and 600 cd/m² for large screens of 60" and more. In this case, the brightness margin anyway will not be superfluous. But with lower indicators, you may have to darken the room somewhat for comfortable viewing.

The level of static contrast provided by the TV screen.

Contrast in a general sense is the ratio in brightness between the brightest whites and the darkest blacks that the screen can produce. Other things being equal, the higher the screen contrast, the better the quality of colour reproduction and detail, the lower the likelihood that it will be impossible to see details in too bright or too dark areas of the image. Static contrast, on the other hand, describes the maximum difference in brightness that can be achieved within one frame without changing the brightness of the image — this is its difference from dynamic contrast (see below).

The values of static contrast are much lower than those of dynamic, but this characteristic is the most "honest". It is on it that the properties of the image seen on the screen at a particular moment depend, it is describes the basic properties of the screen, without taking into account the software tricks provided by the manufacturer in the hardware of the TV.

TV support for high dynamic range technology — HDR.

This technology is designed to expand the range of brightness reproduced by the TV; Simply put, an HDR model will display brighter whites and darker blacks than a regular TV. In fact, this means a significant improvement in colour quality. On the one hand, HDR provides a very "live" image, close to what the human eye sees, with an abundance of shades and tones that a normal screen cannot convey; on the other hand, this technology allows to achieve very bright and rich colours.

However for the full use of this feature, you need not only an HDR TV, but also content (movies, TV broadcasts, etc.) that was originally created for HDR. Also note that there are several different HDR technologies that are not compatible with each other. Therefore, when buying a TV with this feature, it is highly advisable to clarify which version of HDR it supports (HDR10, HDR10 + or Dolby Vision). And the following are found:

— HDR10. Historically the first of the consumer HDR formats, less advanced than the options described below but extremely widespread. In particular, HDR10 is supported by almost all streaming services that provide HDR content, and it is also common for Blu-ray discs. Allows to work with a colour depth of 10 bits (hence the name). At the same time, devices of this format are also compatible wi...th content in HDR10+, although its quality will be limited by the capabilities of the original HDR10.

— HDR10+. An improved version of HDR10. With the same colour depth (10 bits), it uses the so-called dynamic metadata, which allows transmitting information about the colour depth not only for groups of several frames, but also for individual frames. This results in an additional improvement in colour reproduction.

– Dolby Vision. An advanced standard used particularly in professional cinematography. Allows to achieve a colour depth of 12 bits, uses the dynamic metadata described above, and also makes it possible to transmit two image options at once in one video stream — HDR and standard (SDR). At the same time, Dolby Vision is based on the same technology as HDR10, so in modern video technology this format is usually combined with HDR10 or HDR10+.

A decoder can be broadly described as a standard in which digital audio (often multi-channel) is recorded. For normal playback of such sound, it is necessary that the corresponding decoder is supported by the device. Dolby Digital and DTS were the first in multi-channel decoding, gradually improving and introducing new features. The final stage for 2020 is Dolby Atmos and DTS X decoders.

– Dolby Atmos. A decoder that uses not a rigid distribution of sound across channels, but the processing of audio objects, due to which it can be used with almost any number of channels on a reproducing system — the sound will be divided between channels so that each audio object is heard as close as possible to its proper place. When using Dolby Atmos, ceiling speakers (or speakers facing the ceiling) are highly desirable. However, in extreme cases, you can do without them.

— DTS X. An analogue of the Dolby Atmos described above, when the sound is distributed not through individual channels, but through audio objects. The digital signal contains information about where (according to the director's intention) the object audible to the user should be and how it should move, and the processor of the reproducing device processes this information and determines exactly how the sound should be distributed over the available channels in order to achieve the required localization. Thanks to this, DTS X is not tied to a specific number of audi...o channels — there can be as many as you like, the system will automatically divide the sound into them, achieving the desired sound. Also note that this decoder allows you to separately adjust the volume of dialogues.

Types of digital tuners (receivers) provided for in the design of the TV.

Such tuners are necessary for receiving digital TV broadcasts; for normal operation, the broadcast standard must match the type of tuner (with some exceptions, see below). Note that the receivers are also available as separate devices; however, it is easier (and often cheaper) to buy a TV with a built-in tuner of the desired format. In modern TV you can find terrestrial tuners DVB-T2, cable DVB-C and satellite DVB-S and DVB-S2, here are their main features:

— DVB-T2 (terrestrial). The main modern standard for digital broadcasting. Such broadcasting has a number of advantages over traditional analogue broadcasting: it allows higher resolution and multi-channel audio transmission, with better sound and picture quality, and this quality is fully preserved until the signal weakens to a critical level. However, in some countries digital terrestrial broadcasting is just being put into operation, so it will not hurt to check the availability of DVB-T2 coverage in your area.

— DVB-C (cable). The main modern standard for digital broadcasting in cable networks. Despite the advent of the more advanced DVB-C2, it still continues to be widely used, and most likely this situation will not change for a long time.

— DVB-S (satellite). The first...generation of the digital DVB standard for satellite broadcasting. Nowadays, it is relatively rare due to the advent of a more advanced DVB-S2, which is also backwards compatible with the original DVB-S.

— DVB-S2 (satellite). The most advanced and popular of today's digital satellite broadcasting standards. Being the heir to DVB-S, has retained compatibility with it; therefore, manufacturers often limit themselves to installing only a DVB-S2 tuner on their TVs — it allows you to receive both major satellite broadcast formats.

The ability to display on the TV screen "pictures" from several sources at once. Usually, in the picture-in-picture mode, a small window is displayed in the background of the main image (or several such windows), which is displayed in full screen, in it you can see an additional image. One of the most popular ways to use this “multitasking” is to skip commercial breaks in TV broadcasts: for this time, you can switch the main image to a more interesting channel, and leave the ad in the auxiliary window to not miss the end of the commercial and continue watching. It is worth considering, however, that the images for each window must come from different sources — in other words, it will not work to turn on two channels at the same time from one tuner.

— VRR. VRR (Variable Refresh Rate) adaptive frame rate synchronization technology allows you to adjust the refresh rate of the image on the TV screen in real time in accordance with the frame rate output by the game console or connected computer. The function ensures smooth rendering of dynamic scenes, eliminates frame breaks, and guarantees comfortable and stable gameplay. Realizable technology with standard HDMI v 2.1.

— ALLM. Automatic low latency mode for games (Auto Low Latency Mode). The TV switches to game mode when it detects a game console connection. Reducing the output delay on the TV panel screen is provided by suspending part of the image processing functions. The ALLM mode can also be useful for karaoke and video calls.

eARC. HDMI v 2.1 has an enhanced eARC (enhanced Audio Return Channel). The technology allows you to send higher quality audio from your TV to your soundbar or AV receiver. It claims to support the latest high bit rate audio formats up to 192 kHz, uncompressed 5.1 and 7.1, and 32-channel uncompressed audio. eARC also supports Dolby TrueHD, DTS-HD Master Audio, DTS:X, Dolby Atmos.

— CEC. The CEC (Consumer Electronics Control) system is designed for remote control of equipment connected to the TV using a single remote control. The devices are connected to the TV panel using an HDMI cable.