Comparison TCL 65C745 65 " vs TCL 65QLED860 65 "

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.

Dynamic Scene Index (DSI) provided by the TV screen.

DSI is a rather specific parameter that can be called "visible framerate". Its appearance is due to the fact that a high frame rate is highly desirable for dynamic scenes — it provides smooth images and good detail of moving objects. However, for technical reasons, it is not possible to achieve indicators above 200 Hz in most screens. In order to remedy the situation, manufacturers use special technologies that create the effect of increasing the frame rate.

Such technologies may have different names, but they have the same principle of operation — inserting additional frames between the "own" frames of the video being played. And the dynamic scene index describes the overall effectiveness of such technology used in a TV. For example, a DSI of 200 Hz means that the image quality on the screen approximates a frame rate of 200 Hz, although the actual frame rate is often as low as 50-60 Hz.

In the most advanced models, the dynamic scene index can be up to 3000 Hz, and options above 3000 Hz are considered to be TVs with a high dynamic scene index. However, it is worth noting that such specifications are more of an advertising ploy than a real advantage: in fact, the threshold for human perception is 400 – 500 Hz, a further increase in the DSI does not give a clearly visible improvement in the image.

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+.

TV compatibility with special frame synchronization technologies used in AMD graphics cards.

You should pay attention to this parameter if you plan to use the TV as a gaming monitor for a PC or laptop with an AMD graphics adapter. Special timing technologies are used to match the screen refresh rate to the frame rate of the incoming video signal. Such a need arises for the reason that the frame rate issued by the graphics card can “float” when the load on the video adapter changes (this is especially true for demanding games); and if this frequency does not match the screen refresh rate – tears and other unwanted artifacts appear on the image.

The AMD technology used to eliminate this effect is called FreeSync. Nowadays, it is presented on the market in three versions — the original FreeSync and two extended ones:

– AMD FreeSync Premium Pro. The most advanced and functional version, formerly known as AMD FreeSync 2 HDR. In addition to refresh rate sync, it also includes support for HDR (see above), output at a frame rate of at least 120 Hz at Full HD resolution, as well as low frame rate compensation (LFC). The essence of LFC is that when the frame rate of the original video signal falls below the minimum frequency supported by the screen, the same frame is displayed on the screen several times, which allows to maintain the maximum smoothness of the “picture”.

— AMD FreeSync Premium. A somewhat s...implified version compared to FreeSync Premium Pro. It does not provide working with HDR, otherwise it is completely similar.

The brand of the speaker system installed in the TV.

This item is indicated if the TV is equipped with advanced sound system, which is noticeably superior in quality to conventional speakers. Such information further emphasizes the high level of the device. At the same time, the specifications usually do not contain the full name of the speaker system, but only the brand name — for example, Bang & Olufsen, Harman Kardon, JBL, etc.: even such information is quite enough in this case.

The nominal power of the sound produced by the TV's sound system.

The larger the screen and the greater the estimated distance to the viewer, the more powerful the sound system must be in order to be heard normally. Manufacturers take this moment into account, moreover, most often they also provide a solid volume margin. So if a TV is bought for home viewing in a quiet, calm environment, you can not pay much attention to the sound power: it is guaranteed to be enough for such a usage. It makes sense to specifically look for models with high-power speakers for a noisy environment — for example, a cafe or other public space. Detailed recommendations on this matter can be found in special sources, but here we note that even in such cases, connecting external speakers can be a good alternative.

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.