Audio format
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.
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.
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).
Rated power
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).
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.
Sensitivity
The sensitivity value determines the volume of the projector when a signal of a certain power is applied to it. Given the same input power and impedance, a more sensitive system will produce higher volume.
This parameter is important primarily when operating the projector with an external amplifier. At the same time, models with values up to 88 dB are considered low sensitivity, 88 – 92 dB are considered medium, and more than 92 dB are considered high sensitivity.
Wireless subwoofer
The presence of a
wireless subwoofer in the design of the sound projector.
Any subwoofer enhances the bass response, delivering rich bass. The advantage of a wireless subwoofer is the ability to install it almost anywhere in the room without the hassle of laying wires — this makes it easier to adjust the sound to specific conditions. In addition, such subwoofers can have a fairly solid speaker size — 200 mm or more (see below for more details). However note that wireless acoustics require their own power source and significantly affect the cost of the projector.
Acoustic design
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.
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").