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.
Tweeter size
Size of the high-frequency speaker(s) included in the speaker design.
Size affects the amount of space required to install the speaker. However, high frequencies do not require large diffusers, so this dimensions is usually small and does not significantly affect the overall dimensions of the speaker system. The only exception is individual high-frequency tweeters (see "Type"), where the overall dimensions of the housing are directly related to the dimensions of the diffuser.
Midrange speaker diameter
The diameter of the midrange speaker(s) provided in the speaker. Midrange in this case may also mean a combined woofer/midrange speaker or an emitter of broadband acoustics (see "Type").
The size of the midrange speaker is often a key parameter that determines the overall dimensions of the acoustics and, accordingly, the requirements for its installation location. Exceptions can only be found among models with separate woofers (see below). But from the point of view of acoustics, a larger size allows you to achieve higher power and richer sound, including on bass.
Mounting depth
The mounting depth of car audio is, in fact, the size of the speaker in depth. Note that for component sets (see "Type") this parameter is given for the largest speaker, and for case models it is generally irrelevant.
The mounting depth, along with the diameter of the speaker (see above), determines the amount of space needed to mount the speaker — in this case, how deep a niche would be required for normal mounting. At the same time, the larger the speaker, the larger, usually, the installation depth. And with similar diameters of equal size, a more powerful model is likely to be more “deep”.
The smallest amount of space —
up to 15 mm deep — is required by some tweeters. A depth
of 16 – 30mm is normal for tweeters and very shallow for general range speakers, most of these models have a depth
of 30mm or more. At the same time, full-range speakers are usually "recessed" by
less than 60 mm, component systems — by
less than 90 mm, and
more depth may be required only for some coaxial and mid-range models and, oddly enough, tweeters.
