Rated power
Rated power of the speaker system. Most often, the average (rms) sound power is indicated as the nominal one.
The most obvious point associated with this characteristic is sound volume: the more powerful the sound system, the louder the sound it can produce, all other things being equal. In addition, compatibility with an external amplifier depends on this indicator: its power should not exceed the power of the sound system, otherwise overloads and damage to the speakers are possible.
Max. power
The maximum power of a short-term (up to several seconds) incoming signal that the speaker can withstand without physical damage. Just like the nominal power, it matters for the selection of acoustics for an amplifier (or vice versa): it is believed that the maximum power of the speakers should be at least 2 times higher than the maximum power of the signal source.
Sensitivity
This parameter determines the volume of the sound of a particular speaker when a certain standard signal is fed to it. Typically, this is considered a 1 W signal with a frequency of 1000 Hz. The higher the sensitivity, the less the speaker is demanding on the power of the amplifier. So, it is believed that for acoustics connected directly to the car radio, the sensitivity should be 80 dB or more; for less sensitive systems it is recommended to use a separate amplifier.
External crossover
A crossover is a part of the speaker system that divides the overall signal into separate frequency bands that are fed to the corresponding speakers (for more details, see "Number of bands"). All multi-band speakers have their own crossover (component and coaxial, see "Type"); it is usually placed directly in the speaker cabinet. However, in some models, usually the most advanced, the crossover can be made as a separate device, in its own case. It is believed that such crossovers provide better sound quality and introduce less distortion into it; in addition, they often provide the possibility of fine tuning the sound.
Woofer Diameter
The diameter of the subwoofer (speakers) provided in the speaker.
This size is indicated only for models with separate bass drivers. In such acoustics, it is the low-frequency emitter that is the largest (this is due to the physical features of the bass range). Accordingly, the space occupied by the entire system is determined mainly by the diameter of the woofer. And since the power and richness of the bass also directly depends on the size of the radiator, when choosing, one has to proceed from a compromise between the capabilities of the acoustics and the available space in the car.
