Comparison LG SK5 vs LG SJ7

The audio format produced by a sound projector is actually the largest number of individual audio channels supported by the device. Note that in this case we are talking about the number of real channels, that is, channels for each of which at least one speaker is allocated; Models that support virtual surround sound can give the listener the impression of more channels than there actually are (see below for more details).

The sound format is indicated by two or three numbers separated by a dot. The first indicates the number of main channels, the second - the number of subwoofers, the third - the number of additional vertical radiators. For example, 2.1 format corresponds to stereo sound (2.0) supplemented by a subwoofer. And the conditional 3.1.2 format includes left, right and center channels, a subwoofer, left and right vertical speakers.

Sound projectors that support a more advanced sound format than 3.1 are designated in our catalog as multi-channel. The classic multichannel audio format is 5.1, but there are other options. In any case, a large number of real channels contributes to the fidelity of the reproduced sound and simplifies setup compared to virtual surround sound systems, but is also more expensive.

The most common sound formats are: 2.0, 2.1..., 3.0, 3.1, 4.1, 5.1, 5.1.2, 7.1.

The ability of the projector to output a video signal in Ultra HD (4K) resolution — 3840x2160. This is the highest resolution used in modern consumer video equipment — 4 times higher than Full HD. However, note that this feature significantly affects the price of the projector, and to view such a video signal, you will need an appropriate screen. Therefore, it makes sense to specifically look for an UltraHD device only if you initially plan to connect it to a screen of the appropriate resolution.

This feature requires the projector to have at least one HDMI output (see below). In this case, the video signal source can be either an external device or the projector itself, operating in the format of a media centre (for example, a model with direct playback from USB media).

The total power rating of the sound projector speakers (including subwoofer, if present).

This parameter is often used to estimate the overall sound volume of the device, but this is not entirely true. The fact is that the actual sound volume is determined mainly by the power of the main speakers of the sound projector, and the total power is the sum of this power and the power of the subwoofer. Therefore, models with the same power rating can vary markedly in actual volume: for example, a 150-watt soundbar with a 50-watt subwoofer will be louder than a 100-watt projector with a subwoofer of the same power, although in both cases the rated power will be equal to 200 watts.

Summing up, we can say that it is possible to evaluate the volume by rated power only if the sound projector is not equipped with a subwoofer — in such models, the rated power is equal to the power of the main speakers. In other cases, it is worth focus on the power of the soundbar and the power of the subwoofer directly stated in the characteristics (see below for both).

Impedance is the projector's resistance to alternating current, or more precisely, to the analog audio signal input from an external power amplifier. Actually, this parameter is of practical importance precisely if the device is planned to be used with an external amplifier. Ideally, the projector's impedance should match the impedance for which the amplifier is designed - otherwise, the volume may either decrease (if the impedance is too high), or distortion, overload, and even damage to the acoustics (if the impedance is too low) may occur.

Higher impedance is also thought to reduce the likelihood of interference. However, modern speakers (including sound projectors) have standard impedance values of 4, 6 or 8 ohms - the difference is not so great that the differences in sound quality are noticeable.

Acoustic design of the subwoofer used by the sound projector.

— Closed type. The simplest design option is a speaker installed in a closed case. Such subwoofers have a relatively low volume, but are distinguished by good sound fidelity and a minimum of distortion.

— Bass-reflex type. Subwoofers equipped with a phase inverter - a special tube connecting the inner volume of the case with the outer space. Such equipment improves the volume and saturation of the sound, but increases the likelihood of interference (primarily the rumble of air in the pipe).

— With a passive radiator. The passive radiator is actually a speaker without a coil and a magnet, installed in the subwoofer cabinet along with the main speaker. The purpose of such a radiator is similar to the phase inverter described above, except that it is less susceptible to interference.

The rated power of the subwoofer included in the design or delivery of the sound projector.

The higher the power, the louder the sub can sound, the richer the bass it can provide. On the other hand, an increase in power inevitably promises an increase in the size and cost of the speaker. Therefore, an overly powerful subwoofer is just as undesirable as one that is too weak. Detailed recommendations for selecting power for the size and acoustic characteristics of a particular room can be found in special sources.

Note that the external subwoofer in soundbars should be approximately twice as powerful as the soundbar in order to prevent sound sags at maximum volume. So, if the total output power of the speaker system is 300 watts, then 100 of them should come from the soundbar alone, and 200 should go directly to the subwoofer.

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. The first signs of multi-channel decoding were Dolby Digital and DTS, gradually improving and introducing new features. The final stage for 2020 is Dolby Atmos and DTS X decoders.

Dolby Atmos. A decoder that does not use 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, in-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, D...TS X is not tied to a specific number of audio 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. A separate variant of DTS X is the DTS Virtual:X decoder for providing surround sound without the use of additional upward speakers on the soundbar. You can rely on just two channels and a separate subwoofer to achieve the desired DTS Virtual:X effect. A separate variation of DTS X is the DTS Virtual:X decoder to provide surround sound without the need for additional upward-firing speakers on the soundbar. DTS Virtual:X can rely on just two channels and a separate subwoofer to achieve the desired effect.

— IMAX Enhanced. The IMAX Enhanced Mark of Conformity is awarded to equipment that meets the audio certification requirements of IMAX Corporation. Combined with DTS audio technology to deliver signature IMAX theater-like sound in the home. The most accurate reproduction of such audio is possible in systems with a large number of channels (5.1 or more). Note that for a fully immersive experience, IMAX Enhanced certification must also apply to video equipment for playing content (TV, projector, etc.).

— USB-A. This refers to a USB port that allows you to connect external drives (flash drives, hard drives) to the projector and play content directly from them. Models with video outputs (see below) can often function as a media center, outputting video signals to a TV or another external screen.

— USB-C. Used in soundbars for transmitting digital audio with minimal quality loss, replacing traditional AUX and optical ports. Unlike analog connections, USB-C transmits sound without distortion and can support high-resolution audio streams, including Hi-Res formats. It also allows for simultaneous audio and power transmission, simplifying the connection to devices. However, this port is mainly relevant for portable devices, and its primary purpose is to connect a soundbar to a laptop.

— mini-Jack (3.5 mm). The 3.5 mm jack can be used in various interfaces; in this case, it refers to a line audio input with a mini-Jack socket. This input is mainly used to connect portable audio equipment (players, smartphones) to a sound projector.

— RCA. Technically, RCA (commonly called "tulip") is a type of connector that can be used in different interfaces. However, the term "RCA input" usually refers to line inputs for connecting an analog stereo signal. Note that this input consists of two RCA cable sockets, as one cable ca...n only transmit one audio channel.

— Optical. Connector for connecting a digital audio signal via a TOSLINK fiber optic cable. This interface allows for multi-channel sound transmission and is practically immune to electrical interference; its drawback is the fragility of the cable.

— Coaxial S/P-DIF. Connector for connecting a digital audio signal via an electrical cable with an RCA connector (not to be confused with the line RCA described above). Similar to the optical input described above, including the ability to transmit multi-channel sound through a single connector. At the same time, the coaxial cable is less delicate but more sensitive to electrical interference (therefore, a specially shielded cable is preferable for such a connection).

— Composite. This refers to not a full-size composite interface of three connectors, allowing audio and video signal transmission, but only one connector for working with video. Since sound projectors do not reproduce images, the composite input is used to transmit a video signal through the projector to another device, such as a TV. The composite video interface does not support HD and lacks high quality; on the other hand, it is widely used and can work even with outdated video equipment. This input usually uses a yellow RCA ("tulip") connector.

— Component. An input designed to receive an analog video signal for further transmission to another device—TV, video projector, etc. This connection usually uses three RCA connectors, each transmitting its component of the video signal (hence the name). Thanks to this, the component interface offers good bandwidth and picture quality, supports HD, and is considered the most advanced modern standard for analog video.

— IR Control Input. A connector for connecting an external infrared remote control receiver. When correctly positioned, this receiver allows the use of a remote control even from locations where the signal from the remote cannot reach the main (built-in) sensor—such as another room. Note that the receiver can be a specialized device or another component of the audio system—such as an amplifier with an IR control output.

The ability to control the soundbar, in addition to the standard push-button from the device case, also includes control from the remote control, the TV remote control to which the acoustics are connected, through the application from a smartphone or tablet, and in some cases using a voice assistant. More details about each of them:

— Remote control. The presence in the configuration of the classic remote control on IR sensors, like those used in TVs. It can contain much more settings functions than the controls on the body of the device and, of course, makes it easier to control the soundbar.

— TV remote control (HDMI-CEC). Connecting the soundbar via the HDMI port allows you to control it via the HDMI-CEC protocol via the TV remote control. This solution will reduce the number of remotes in the room and facilitate the comfort of the settings. However, the functionality of the "non-native" remote control may be limited. In this case, the compatibility of the TV and the soundbar can be achieved using other protocols (not necessarily HDMI-CEC).

— Smartphone control. The ability to control the soundbar through the application. This makes it easier to “search” for the remote control, because the phone is always at hand. The application also has extensive settings and such control is highly likely to be supported by t...he TV, which allows you to execute absolutely any commands from your smartphone for a comfortable pastime on the TV.

— Voice assistant. This is not about the assistant built into the soundbar itself, but about compatibility with external devices that have this function (for example, with a smartphone or tablet). But even such compatibility allows you to give commands to the voice projector by voice — this is often more convenient than more traditional control methods. The specific set of supported commands and languages may vary depending on the voice assistant and its specific version. And among the most popular at the moment are Google Assistant, Apple Siri, Amazon Alexa.