Comparison JBL Stage2 604C vs JBL Stage3 607C

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.

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.

The term "impedance" refers to the electrical resistance of AC systems whose DC resistance is very low, such as loudspeakers. In modern car audio, the most common impedance is 2, 4 or 8 ohms. This parameter has practically no effect on the sound quality — it serves to select the optimal combination of acoustics and an external amplifier. If the speaker impedance is higher than that for which the amplifier is designed, the sound will be quieter than necessary, and if the impedance is lower, distortion in the sound is possible.

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.

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.

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.