Comparison Harman Kardon SB 20 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).

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.

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 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.

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").