Comparison Samsung QE-55Q70B 55 " vs Samsung QE-55Q70A 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 turned 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 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.

The response time can be described as the maximum time required for each pixel of the screen to change brightness, in other words, the longest time from the receipt of a control signal to the pixel until it switches to the specified mode. The actual switching time may be less — if the brightness changes slightly, it can be calculated in microseconds. However, it is the longest time that matters — it describes the guaranteed response speed of each pixel.

First of all, the frame rate is directly related to the response time (see the relevant paragraph): the lower the response time, the higher the frame rate can be provided on this sensor. However, the actual frame rate may be less than the theoretical maximum, it all depends on the TV. Also note that the overall image quality in dynamic scenes depends primarily on the frame rate. Therefore, we can say that the response time is an auxiliary parameter: the average user rarely needs this data, and in the specifications they are given mainly for advertising purposes.

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.

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.

The electrical power normally consumed by the TV. This parameter strongly depends on the screen size and sound power (see above), however, it can be determined by other parameters — primarily additional features and technologies implemented in the design. It is worth noting that most modern LCD TVs are quite economical, and most often this parameter does not play a significant role — in most cases, power consumption is about several tens of watts. And even large models with a diagonal of 70 – 90" consume about 200 – 300 W — this can be compared with the system unit of a low-power desktop PC.