Comparison LG SJ3 vs Sony HT-CT390

The projector supports the virtual surround function.

The purpose of this feature is that due to special sound settings and the reflection of sound beams from the walls of the room, the listener hears more channels than are actually available in the projector (see "Audio Format"). For example, a 3.1 system with virtual surround sound can produce sound similar to 5.1 surround sound. This allows you to achieve the effect of "immersion" in sound without increasing the number of channels and the cost of the projector. On the other hand, the reliability of such sound is usually noticeably worse than that of real surround sound, and the overall quality is highly dependent on the characteristics of a particular room.

Note that the virtual surround function is specified for 2.0, 2.1, 3.0, 3.1 format systems. In more advanced multi-channel systems, there are a priori additional channels for reproducing surround sound.

The nominal power of the speakers installed directly in the soundbar, excluding the subwoofer (in models with a built-in subwoofer, respectively, only the power of the main speakers is taken into account).

This indicator directly determines the overall volume of the sound projector; It is worth choosing according to this parameter taking into account the specifics of the room in which the projector is planned to be installed: the larger the room and the greater the distance to the viewer, the higher the power should be, otherwise the soundbar will not be able to effectively sound the scene. Detailed recommendations on the optimal power for different situations can be found in special sources.

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.

The diameter of the speaker in the subwoofer used by the sound projector.

It is believed that the larger the speaker, the louder the sub and the deeper and richer sound it can provide. Models up to 200 mm in size are entry level; This is exactly the size that built-in subwoofers usually have (see above). But free-standing bass speakers can use larger speakers, up to 254 mm (10").

— Airplay. Wireless technology for connecting an external signal source to the projector. Developed by Apple, it is mainly used to connect with its devices (for example, iPad tablets or MacBook laptops), although it is also used by other manufacturers. AirPlay allows you to transfer not only sound, but also text and graphic information, and even video, which can be useful when connecting the projector to a TV. This technology, by definition, means support for Wi-Fi (see below), because. it is based on this interface.

— Airplay 2. The second generation of the AirPlay technology described above, introduced in 2018. Among the main innovations of this version is support for the "multi-room" format, that is, the simultaneous transmission of several audio signals to different compatible devices installed in different places. In this way, you can, for example, turn on an online broadcast of a news programme in the living room, relaxing music in the bedroom, etc. In addition, AirPlay 2 received a number of other improvements — improved buffering, the ability to stream to stereo speakers, as well as support for voice control via Siri.

— Chromecast. The original name is Google Cast. A technology for broadcasting content to external devices developed by Google. Allows you to transmit an audio signal from a PC or mobile device to the soundbar, the broadcast is standar...dly carried out via Wi-Fi, while the receiver and signal source must be in the same Wi-Fi network (Chromecast media players are an exception). Note that in signal sources (smartphones, tablets, PCs, etc.), Chromecast is implemented at the level of individual applications. For example, at the time of its creation, this feature was available, among others, in the YouTube and Netflix apps for Android and iOS, as well as in the web versions of these apps for Chrome. Thanks to this format, this technology is extremely widespread nowadays, and the ability to connect a particular gadget to an audio system with a Chromecast is usually limited to the ability to install appropriate applications on this gadget.

— Wi-Fi. Wireless technology with multiple applications. One of them is connecting to a computer network; in sound projectors, it is primarily used for local resources (see DLNA below) or AirPlay technology (see above), as well as for controlling the projector over a network. Another option is to connect directly to other devices. The possibilities of such a connection in different models may also be different; one of the most popular options is remote control of the projector from a smartphone, tablet, etc.

— Bluetooth. Wireless technology designed to directly connect different electronic devices to each other. In sound projectors, it is primarily used to broadcast audio wirelessly from another Bluetooth device, such as a smartphone or laptop. However, there may be other options — for example, connecting wireless headphones to the projector itself or remote control from the same smartphone. It is worth noting here that the sound quality when transmitting via Bluetooth is somewhat lower than with a wired connection; on the other hand, this is offset by convenience, and some models of sound projectors may even have a "sound restoration" system.

— NFC. NFC is a wireless communication technology over short distances, up to 10 cm. In sound projectors, it is used mainly as an auxiliary, to facilitate connection via Wi-Fi or Bluetooth. It looks like this: instead of manually digging into the settings, just bring an NFC-compatible device to the projector chip and confirm the connection.

— FM radio. The projector has a built-in FM tuner. This function actually turns the device into a full-fledged radio receiver, allowing you to receive broadcasts on the FM band (which broadcasts most music radio stations). Note that some models with a tuner may support other bands, such as AM or digital DAB.

— LAN. A standard wired connection to a computer network, also known as Ethernet or RJ-45. Like Wi-Fi (see above), in sound projectors it is used primarily for working on a local network; however, LAN capabilities can include both playback of network content via DLNA (see below) and control of projector settings via a network from a computer. A wired connection is not as convenient as Wi-Fi due to the need to run a cable, but it is more reliable and can come in handy when the air is “loaded” (an abundance of Wi-Fi devices nearby).

— DLNA. A technology used to connect various electronic devices into a single digital network with the ability to directly exchange content. Devices for which support for this standard is claimed are able to effectively interact regardless of the manufacturer. And the network itself works on the basis of a conventional computer "local area", connection to it is carried out via LAN or Wi-Fi (see above). In sound projectors, DLNA can be used, for example, to play music from a computer hard drive.

— RS-232. A service interface used to connect the sound projector to a computer and control the sound settings from the PC through a special programme. On some models, it can also be used to update the firmware.

— Connecting an iPod. Special interface for connecting Apple iPod players. Most often it is based on a regular USB connector, to which the player is connected via an adapter cable; however, it may look like a dock — a stand with a proprietary connector, where the gadget is directly placed. Anyway, connecting in this way provides not only playing music from the player, but also other possibilities — for example, switching tracks from the projector's remote control, charging the battery, etc.

— Wireless connection to TV. Ability to connect the sound projector to the TV wirelessly. The advantage of this option is obvious: it eliminates the hassle of additional cables. On the other hand, a wireless connection is usually based on a certain proprietary technology (LG Sound Sync, TV SoundConnect, etc.) and requires a TV that supports the corresponding technology to work. This limits the use of this feature. In addition, such a connection is more susceptible to interference than a wired one, and “wireless” projectors are more expensive than wired ones. Therefore, it is worth specifically looking for a model with such a function if you have a TV with wireless technology support and at the same time the absence of extra wires is fundamental.

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.).

The number of HDMI outputs in the design of the sound projector.

HDMI is the most popular modern interface for working with HD content, it allows you to transmit high-definition video simultaneously with multi-channel audio over a single cable. If you have multiple outputs, you can connect multiple signal receivers to the projector at the same time and switch between them from the remote control without touching the wires.

The total number of speakers installed in the sound projector housing (external subwoofer is not taken into account in this calculation).

Given the same audio format (see above), more speakers typically provide greater fidelity and more precise localization of individual sound sources. This is especially true for models with virtual surround sound.