Comparison LG 55SM8600 55 " vs LG 55SK8500 55 "

The highest frame rate supported by the TV.

Note that in this case we are talking specifically about the screen’s own frame rate, without additional image processing (see “Index of dynamic scenes”). This frequency must be no lower than the frame rate in the video being played - otherwise there may be jerks, interference and other unpleasant phenomena that degrade the quality of the picture. In addition, the higher the frame rate, the smoother and smoother the movement in the frame will look, and the better the detail of moving objects will be. However, it is worth noting here that playback speed is often limited by the properties of the content, and not by the characteristics of the screen. For example, films are often recorded at a frequency of only 30 fps, or even 24 - 25 fps, while most modern TVs support frequencies of 50 or 60 Hz. This is enough even for viewing high-quality content in HD resolutions (speeds above 60 fps in such video are extremely rare), but there are also “faster” screens on the market: 100 Hz, 120 Hz and 144 Hz. Such speeds, as a rule, indicate a fairly high class of the screen; they also often imply the use of various technologies designed to improve the quality of dynamic scenes.

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 support for one or another brightness / contrast enhancement technology.

Usually, in this case, software image processing is implied, in such a way as to improve brightness and/or contrast (if necessary). Specific processing methods may be different — in particular, in some cases we are actually talking about turning standard content into HDR (see above), and some manufacturers do not specify technical details at all. The effectiveness of different technologies can also be different, and besides, it is highly dependent on the specific content: in some cases, the improvement will be obvious, in others it may be almost imperceptible. Also note that this feature is not always useful, so in most models it is turned off.

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.

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.

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, MHL, DLNA, Bluetooth, in rare cases NFC. As a control, in addition to the classic remote control, there can be multimedia air mouse remote, 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 differe...nt 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 (see below), 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.

— TV shows recording. The ability to record TV programmes viewed on the TV. In most cases, it is supposed to record to a USB flash drive or other external USB drive, but there are other options: if you have a card reader (see "Inputs"), recording to a memory card can be provided, and some advanced TVs are equipped with quite capacious own drives. But this feature can be useful in cases where you need to save the broadcast — for example, so that someone can watch it later, or to save a TV programme with a family member to your home collection. In addition, many TVs with this feature also provide a Time Shift mode: if you need to leave the room, you can “pause the broadcast” and the TV will start recording it, and upon returning, you can continue watching from the point at which it was interrupted. Note that some TVs may require the installation of additional software to record TV programmes; for such models, this function is not always indicated, although it is technically available.

— MHL support. TV support MHL interface. This interface is used in portable electronics (smartphones, tablets) to transfer high-definition video and multi-channel audio to an external screen. In fact, it is a combination of microUSB and HDMI (see below): from a portable device, the signal is output through the universal microUSB port, and the TV receives video and audio through the MHL-enabled HDMI port, while simultaneously charging the connected gadget. The MHL bandwidth is sufficient for high-definition video and multi-channel audio.

— 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.

— NFC. TV compatible with NFC technology; the NFC itself, usually, is built into the remote control or is made as a separate tag; installing it in the TV case is not very convenient. This technology provides wireless communication over short distances, usually up to 10 cm. Theoretically, the methods of its application can be different, but specifically on TVs, it is mainly used to facilitate communication via Wi-Fi or Bluetooth: just bring an NFC-compatible gadget (for example, a smartphone ) to the TV chip — and the devices will recognize each other automatically and either connect immediately, or the user will be required to confirm the connection. Anyway, it's easier than setting up the connection manually.

— DLNA support. The TV supports DLNA — Digital Living Network Alliance. This standard was created so that various types of home and portable electronics — smartphones, tablets, media centers, computers, etc. — was possible to combine into a single network and easily exchange content within this network, regardless of the model and manufacturer of individual devices. In the case of a TV, this means that you can directly stream video from other devices, such as a smartphone, to it via the network. The network itself is built on the basis of the usual local area network, both a wired LAN interface and wireless Wi-Fi can be used to connect to 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.

— Multimedia (air mouse remote). Air mouse remotes are devices that have a gyroscope, which allows you not only to switch menu items with the “↑”, “↓” buttons, but to use the remote control as a mouse. By pointing it at the TV screen, a cursor will appear that moves in the direction of the remote control. This makes management easier and faster.

— 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.

The TV's connectivity is based not only on wireless technologies (described above), but also on a wired connection. In particular, video transmission can be carried out through VGA, Component, Composite, SCART connectors. Some of them also provide sound transmission, in addition to which there may be a mini-Jack (3.5 mm). and other ports for interconnection with external devices. More about them:

— USB. Connector for connecting external peripheral devices. The presence of USB means at least that the TV is capable of playing content from flash drives and other external USB media. In addition, there may be other ways to use this input: recording TV programs to external media, connecting a WEB camera (see same paragraph), keyboard and mouse to use the built-in browser and other software, etc. The specific set of options depends on the functionality of the TV, it should be specified separately in each case.

— Card reader. A device for working with memory cards, most often in SD format. The main use of the card reader is to play content from such cards on a TV; such an opportunity is especially convenient for viewing materials from photo and video cameras — it is in such devices that memory cards are w...idely used. There may be other ways to use this function — for example, recording from the broadcast or even exchanging files between the card and the TV's storage. It is worth bearing in mind that SD cards have several subtypes — original SD, SD HC and SD XC, and not all of them may be supported by the card reader.

— LAN. Standard connector for wired connection to computer networks (both local and the Internet). Mostly found in models with Smart TV support (including Android TV devices; see related paragraphs). A wired connection is less convenient than Wi-Fi, not as aesthetically pleasing, so manufacturers place more emphasis on a wireless connection, as a result of which the speed indicators of the LAN connector are not indicated, and in some cases may be unacceptable for 4K broadcasts.

— VGA. Analogue video input, also known as D-sub 15 pin. Initially, the VGA interface was developed for computers, but due to the emergence of more advanced standards like HDMI (see below) and technical limitations (the maximum resolution is only 1280x1024, the inability to transmit sound), it is considered obsolete and is used less and less. So it makes sense to specifically look for a TV with such a connector mainly in cases where it is planned to be used as a monitor for an outdated computer or laptop.

— Component. Video interface with 3 connectors, each of which is responsible for its part of the video signal. This separation provides high bandwidth and noise reduction, making the component input the most advanced analogue video interface available today. So, it is capable of working with HD, and in terms of image quality it significantly surpasses S-Video and composite connector, closely approaching HDMI (see below).

— Composite. Combined analogue audio/video interface, it is this connector that is usually called the A/V input. Actually, there are usually three connectors in the composite interface — separately for video and the left/right channel of stereo sound (on TVs with one speaker that do not support stereo, one of the audio connectors is missing). The image quality when working through such an input is not high, and HD formats are not supported at all; on the other hand, the composite interface is extremely widespread not only in modern, but also in outdated equipment like VHS video recorders.

— SCART. The large universal multimedia connector, the largest connector used in today's consumer-grade video equipment. Works mainly with an analogue signal, which is why it is considered obsolete; however, still not falling into disuse. One of the reasons for this "longevity" is versatility: SCART does not have its "own" signal format, this standard only describes the connector. In fact, having the appropriate cables, you can connect different types of incoming signals to such an input — composite, S-Video, etc. Moreover, it is technically possible for such a connector to work as an output (for the same signal types). However the specifications of SCART connectors in different TVs may be different, so a specific list of compatible interfaces needs to be specified separately.

— COM port (RS-232). A connector originally developed for computer technology. It is used as a control on TVs: by connecting the device to a computer, you can control TV parameters and various settings, sometimes quite specific and inaccessible when using a conventional remote control.

— Mini-Jack (3.5 mm). A connector most commonly used as an analogue audio (line) input. One of the options for using such a connector is to connect audio for a video signal transmitted via VGA, S-Video (see above) or another interface that does not support audio transmission. However, with the appropriate cable, any audio source can be connected to the 3.5 mm mini-Jack port, including a mobile device like a smartphone or a pocket player. In this case, the sound can be played both through the speakers of the TV, and on external speakers connected to it. Another option for using this input is to connect a microphone for chatting via Skype.