Subwoofer (RMS)
Rated power of the subwoofer supplied with the home theater. See "Front" above for details on power rating; here we note that subwoofers often have a fairly high power, because. they are designed to cover low frequencies in all audio channels.
Total power (RMS)
The total power rating of all home theater speakers, including subwoofers. The value of the rated power is described in detail in paragraph "Front" above.
Frequency range
The range of audio frequencies reproduced by a home theater speaker system. The wider the range — the richer the sound, the less likely it is that the acoustics will “cut off” part of the low or high frequencies. When evaluating this indicator, one should proceed from the fact that the range perceived by the average human ear is from 16 Hz to 20 kHz. However, modern home cinemas for the most part cover this range completely or almost completely.
Sensitivity
The sensitivity value determines the volume of the speaker system when an external signal of a certain power is applied to it. With the same signal strength and resistance (impedance), more sensitive acoustics provide greater volume.
Impedance
Home theater speaker system AC impedance. Impedance matters when connected to an amplifier: if the impedance of the speaker system is less than that of the amplifier, distortion in sound is possible, if it is higher, the acoustics may sound quieter than we would like. Naturally, in the original home theater sets, the speakers and amplifier are selected with the optimal impedance ratio, so in fact you only have to pay attention to this parameter when you need to connect acoustics to a “non-native” amplifier.
Bass reflex
The phase inverter is a tube installed in the column housing and having an outlet to the surrounding space. Most often, this feature is found in subwoofers, although it can also be used in main acoustics. The length of the tube is chosen so that a signal comes out of the outlet, inverted in phase relative to the signal from the front of the diffuser. This increases the sound pressure and improves the sound of the speakers, however, it can create certain side effects (in particular, associated with the hum of the air flow in the bass reflex pipe). Therefore, the presence or absence of this function is not a clear advantage — it all depends on the preferences of the listener and the design features of a particular speaker.
Active subwoofer
Subwoofer with its own built-in power amplifier. The presence of such an amplifier allows you to "unload" the main amplifier of the cinema, which has a positive effect on the overall volume and sound quality of the speaker system. In addition,
active subwoofers are often equipped with fine-tuning tools that allow you to achieve the desired sound quality without moving the subwoofer around the room.
Number of channels
The number of amplifier channels may be greater than the total number of speakers in the system. This allows you to equip your home theater with new speakers and expand the sound quality of the system as a whole. More specifically, you can read about the appointment of the number of channels in the “Acoustics” paragraph. And this item is especially relevant for 5.1 systems, in which the receiver is equipped with
a 7.1 amplifier thanks to it.
Front
Rated power delivered by the built-in home theater power amplifier per front channel.
Note that in home theaters the rated power of the amplifier output to any channel (any channel, not just the front one) is usually equal to the rated power of the standard speaker installed on this channel (see above). Therefore, many manufacturers do not give the characteristics of the built-in amplifier separately at all — firstly, they are easy to determine from the information about the speakers, and secondly, when using a system with complete acoustics, these data are not required. However, information about the power of the amplifier is indispensable if you plan to use third-party speakers instead of standard acoustics. The rated power of each such speaker must not be lower than the rated power on the corresponding amplifier channel — otherwise, various undesirable phenomena are possible at high volume, from sound distortion to damage to the speaker.
