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.
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").
Inputs
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USB A. In this case, we mean a USB connector that allows you to connect external drives (flash drives, hard drives) to the projector and play content directly from them. At the same time, models with video outputs (see below) can often work as a media centre, outputting the video signal to a TV or other external display.
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mini-Jack (3.5 mm). By itself, the 3.5 mm plug can be used in different types of interfaces; in this case, it means a linear audio input with a mini-Jack socket. This input is mainly used to connect portable audio equipment (players, smartphones) to the sound projector.
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RCA. Technically, RCA (colloquially "tulip") is a type of connector that can be used in different interfaces. However, the term "RCA input" is used to refer only to line inputs for connecting an analogue signal in stereo format. Note that this input consists of two sockets for RCA cables, because. Only one channel of sound can be transmitted through one cable.
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Optical. Connector for digital audio signal connection via TOSLINK fibre optic cable. This interface allows for multi-channel audio transmission and is virtually immune to electrical interference; its disadvantage is the fragility of the cable.
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Coaxial S / P-DIF. A connector for connecting a digital audio signal via an elect
...rical cable with an RCA connector (not to be confused with linear RCA, described above). Similar to the optical input described above, in particular, the ability to transmit multi-channel audio through a single connector. At the same time, a coaxial cable, on the one hand, is not so delicate, and on the other hand, it is sensitive to electrical interference (therefore, it is advisable to use a special shielded wire for such a connection).
— Composite. In this case, we do not mean a full-format composite interface of three connectors that allows you to transmit audio and video signals, but only one connector for working with video. And since sound projectors don't display images, the composite input is used to send video through the projector to another device, such as a TV. The composite video interface does not allow working with HD and is not of high quality; on the other hand, it is widespread and can even be used to work with frankly outdated video equipment. Typically this input uses a yellow RCA plug.
— Component. An input designed to receive an analogue video signal for further transmission to another device — a TV, video projector, etc. This connection typically uses three RCA connectors, each carrying a different video component (hence the name). Due to this, the component interface has good bandwidth and picture quality, it allows you to work with HD and is considered the most advanced modern analogue video standard.
— IR control input. Connector for connecting an external infrared remote control receiver. When properly placed, such a receiver will allow you to use the remote control even in places where the signal from the remote control cannot reach the main (built-in) sensor — for example, in another room. Note that the role of the receiver can be played not only by a specialized device, but also by another component of the audio system — for example, an amplifier with an IR control output.HDMI input
The number of
HDMI inputs 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. Having multiple inputs allows you to keep multiple signal sources connected to the projector at the same time and select the source from the remote without fiddling with reconnecting wires.
Outputs
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To the subwoofer. Dedicated output for connecting an external subwoofer. This is usually a line output that only feeds bass — this eliminates the need for external frequency filters. Such a connector is designed to connect an active subwoofer — a passive one will need its own amplifier. Note that this output can be provided in models equipped with their own subwoofer (see above) — in case the capabilities of this subwoofer are not enough.
— RCA. Despite the fact that RCA connectors are used in various interfaces, the term "RCA output" is usually used only for line output with such connectors. This output is used to send an analogue audio signal to an external device; it usually uses the stereo format and consists of two RCA jacks (one for each channel). In sound projectors, the line output can be useful, for example, for connecting additional acoustics.
— Composite. In this case, we do not mean a full-format composite interface of three connectors that allows you to transmit audio and video signals, but only one connector for working with video. This output is used to connect a sound projector to a TV and work as a media centre. The composite video interface does not allow working with HD and is not of high quality; on the other hand, it is widespread and can even be used to work with frankly outdated video equipment (for example, kinescope TVs). Typically this input uses a yellow RCA plug.
— Component. An outpu
...t used to send an analogue video signal to an external display. It uses three cables (usually with RCA plugs), each of which carries a different video signal component (hence the name). Due to this, the component interface has good bandwidth and picture quality, it allows you to work with HD and is considered the most advanced modern analogue video standard.
— IR control output. An output that allows the sound projector to be used as an external IR receiver for other devices (such as an amplifier or audio receiver). Through this output, the sound projector can transmit received commands from the control panel to the connected equipment. This allows you to install an external device anywhere, even outside the range of the remote control. In addition, this feature is especially useful for some shelf models (see "Installation type"), which, when installed, may cover the IR receiver of the TV. However note that equipment from different manufacturers may be incompatible in terms of control connectors.HDMI output
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.
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.