Virtual surround sound
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.
3D
The ability of the projector to output a video signal in 3D format — that is, a "volumetric" image that has three full dimensions (including depth). Since 3D uses the division of the “picture” of the image into two parts (for the left and right eyes), the format of such a signal differs from the usual two-dimensional one, and not every model is able to work with it. You also need to consider that in order to view 3D content, you need not only a projector, but also a TV (or other playback device) with the appropriate screen capabilities.
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).
Ultra HD (4K)
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).
Frequency range
The audio frequency range supported by the projector's speakers.
When evaluating this parameter, it is worth remembering that the audibility range of the human ear is about 16 – 22,000 Hz (and narrows with age). If the projector's frequency range is narrower, this can result in "cutting" low or high frequencies (however, with a slight narrowing, this effect is almost imperceptible). There are models in which the frequency limit is much wider — however, this is a kind of "side effect" of high-quality acoustics and has no meaning other than advertising.
Also note that a wide frequency range in itself does not guarantee high-quality sound — a lot depends on other parameters of the projector.
Impedance
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.
Subwoofer speaker size
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").
Interfaces
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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.
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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.
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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.HDMI version
HDMI interface version supported by the soundbar.
See the interface itself for more details (“HDMI input”, “HDMI output”), and its versions differ primarily in bandwidth. Here are the current options:
— v 1.4. The earliest of the widespread versions, which, nevertheless, has quite decent features: in particular, it supports 4096x2160 video at 24 fps, and in Full HD the frame rate can reach 120 fps, which already allows you to work with 3D. It has two modifications — v.1.4a and v.1.4b — differing from the original mainly in slightly advanced capabilities for working with three-dimensional content.
-v 2.0. The version introduced back in 2013. The increased bandwidth allowed support for 4K video at frame rates up to 60 fps, as well as up to 32 channels of audio and up to 4 audio streams simultaneously. This version also has two extensions: HDR support was added in the v.2.0a update, and this feature was improved and expanded in v.2.0b.
— v 2.1. An update to the HDMI standard released in 2017. Of the main innovations, support for 8K and 10K video at speeds up to 120 fps has been added, and HDR capabilities have been improved. However it is worth considering that all these features are available only when using special HDMI Ultra High Speed cables.
Number of speakers
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.