Comparison TCL 55C805 55 " vs TCL 55C845 55 "

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 dynamic 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. Formally, the main characteristic of screens is static contrast (see above), but even in advanced matrices it is relatively low. Therefore, manufacturers went to the trick, introducing such a characteristic as "dynamic contrast".

Dynamic contrast ratio is the difference between the brightest whites at the highest screen brightness settings and the darkest blacks at the lowest. These contrast ratios can be quite impressive—much higher than static—however, it is impossible to achieve such values within a single frame, and dynamic contrast ratio is stated more for promotional purposes than for describing the actual specifications of the screen. However, it cannot be said that this indicator is completely unrelated to reality. The fact is that many TVs use automatic brightness control, which changes the settings depending on the characteristics of the image. This control is based on the fact that when displaying bright scenes, there is no need to provide a deep black level, and in dark scenes, high brightness of light areas is not needed — th...ese are the features of the human eye. This means that in bright scenes you can increase the overall brightness, and in dark scenes you can reduce it; the maximum brightness difference achievable in this mode of operation is precisely described by dynamic contrast.

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.

The presence of a subwoofer as part of the TV sound system.

A subwoofer is a specialized speaker for bass and ultra-low frequencies. It makes the sound richer in the bass, which is especially useful when watching adventure films with appropriate sound effects (bumps, explosions), as well as concerts. It should noted that the specifications of built-in subwoofers are usually much more limited than those of external ones; so don't expect cinema-like bass from a TV audio system. However, the advantage in bass quality for such TVs (compared to models without a subwoofer) will still be noticeable.

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.

Among the features of the TV, first of all, it is worth noting its communication features, which include AirPlay 2, Wi-Fi(in particular Wi-Fi 5 and Wi-Fi 6), Miracast, Chromecast, Bluetooth. As a control, in addition to the classic remote control, there can be voice control, voice assistant. As well as special features in the form of Ambilight from Philips. More about them:

— Airplay. TV support for AirPlay technology, usually in the AirPlay 2 version. Initially, this technology was created to broadcast multimedia content from Apple gadgets (iPhone, iPad, etc.) to external devices, including TVs. At the same time, it allows not only to play such content, but also provides many additional features — broadcasting additional information (title of the sound track, album cover), playback control from the TV remote control, etc. In AirPlay 2, in turn, the "multi-room" format was added — the ability to simultaneously broadcast several signals to compatible devices installed in different places at home (for example, a movie on a TV and an online radio programme on sound system in the kitchen). In addition, in this version, support for voice control via Siri has appeared and...a number of technical issues have been improved (in particular, buffering of streamed content).

— Wi-Fi. The presence of a built-in Wi-Fi module in the TV; the supported version of this technology can also be specified in this section. Nowadays, Wi-Fi can be used both for wireless access to the Internet and local networks, as well as for direct connection with other devices (for example, broadcasting video from a smartphone/tablet). The specific application of the wireless connection may be different, depending on the functionality of the TV; in addition to Internet access, examples include DLNA, receiving or transmitting video via Wi-Di or Miracast, and using a mobile gadget as a remote control. However, almost all models with this feature belong to Smart TV (see above).
As for Wi-Fi versions, the most relevant nowadays are Wi-Fi 5, Wi-Fi 6 and Wi-Fi 6E. Also note that, in addition to these Wi-Fi standards, earlier ones are usually supported — so compatibility problems does not occur.

— Miracast. TV support for Miracast technology. This technology allows you to broadcast video and audio signals via Wi-Fi technology (both to the TV and from it to portable electronics), while both devices are connected directly (Wi-Fi Direct) and do not require additional equipment, and the bandwidth is sufficient for Full HD video transmission and 5.1 multi-channel audio. Some time ago, TVs used a similar WiDi technology, but nowadays it is almost ousted from the market, and most manufacturers use Miracast.

— Chromecast. Chromecast technology allows you to quickly and easily stream video and audio from your smartphone, tablet or computer to your TV. In fact, Chromecast is a network media player, because after setting up this function, you can wirelessly display the video recorded on your smartphone on your TV with just one touch.

— Bluetooth. Bluetooth technology (any version) is used for direct wireless communication between different devices. How it is used on TVs may vary, depending on the functionality of a particular model (and version of Bluetooth). So, it is almost mandatory for Bluetooth TVs to be able to transfer sound to wireless headphones or speakers. In addition, other use cases may be provided: connecting keyboards, mice and game controllers, direct file exchange with a laptop, remote control from a smartphone or other gadget, etc. These details should be clarified separately. As for specific versions, in many models these details are not specified at all — for use for the intended purpose, “just Bluetooth” is enough. However, there are exceptions, and here the following options are relevant for modern TVs:

• Bluetooth v4.0. A version that combines traditional Bluetooth 2.1, a high-speed standard for transferring large files, and "Bluetooth Low Energy" for small amounts of information. All subsequent versions are built on these three components (with various improvements), and v 4.0 was the first where they appeared all together.
• Bluetooth v 4.1. Improvement of version 4.0, in which compatibility with mobile devices of the 4G LTE standard has been improved — so that the LTE and Bluetooth modules do not create mutual interference while working nearby.
• Bluetooth v4.2. Further development of version 4.0; updates that are relevant for TVs include mainly improving the reliability and noise immunity of communications.
• Bluetooth v5.0. One of the key improvements in version 5.0 compared to previous editions of the protocol was the presence of two special “Low Energy” modes – increased range (due to reduced speed) and increased speed (due to reduced range).
• Bluetooth v 5.1. Update of the v 5.0 version described above. In addition to general improvements in the quality and reliability of communication, this update has implemented such an interesting feature as determining the direction from which the Bluetooth signal is coming. Thanks to this, it becomes possible to determine the location of connected devices with an accuracy of up to a centimeter (for example, a remote control).
• Bluetooth v 5.2. The next, after 5.1, is the fifth-generation Bluetooth update. The main innovations in this version are a number of security improvements, additional power optimization in LE mode, and a new audio signal format for synchronized parallel playback on multiple devices.
• Bluetooth v 5.3. The Bluetooth v 5.3 wireless protocol was introduced at the beginning of 2022. Among the innovations, it accelerated the process of choosing the communication channel between the controller and the device, implemented the function of quickly switching between the state of operation in a small duty cycle and high-speed mode, improved the throughput and stability of the connection by reducing the susceptibility to interference. In case of unexpected interference in the Low Energy mode of operation, the procedure for selecting a communication channel for switching is now accelerated. There are no fundamental innovations in protocol 5.3, but a number of qualitative improvements are seen in it.

— Ambilight. Screen backlight technology. In this case, the TV case illuminates the wall/partition located at the back, due to which a blurry halo appears around the screen contour in the colour of changing scenes. This effect visually expands the screen area, making watching TV more enjoyable. There are three types of backlighting in total: classic Ambilight (on the sides only), Ambilight Surround (on the sides and top), Ambilight Full Surround (from all sides). But manufacturers continue to work on improving the backlight. So, relatively recently, the Ambilight Spectra backlight has appeared, in which the colour matching algorithm has been significantly improved and the LEDs themselves have been optimized.

— Voice control. TV support for voice control allows you to dictate certain commands through the remote control. However, not all functions are covered by voice control and recognition accuracy may require re-entering the command. If you need a more extensive range of functions, then pay attention to the voice assistant.

— Voice assistant. For a long time now, device control has been shifting to voice commands. For this, certain interfaces and systems are used. The most popular are Amazon Alexa and Google Assistant, as well as Samsung's own Bixby assistant. For "apple" devices, this is Apple Siri, but this technique is not presented on TVs. At the same time, unlike the voice control function, the voice assistant does not just turn on this or that function, mode, makes it louder, quieter, but allows you to perform certain operations in applications, whether it is to launch the desired clip in Youtube or display the weather in the browser.

— 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.