If your car audio system uses coaxial speakers, you probably don't need an additional crossover. ... Even if you add an amplifier into the mix, the built-in speaker crossovers should be more than sufficient. However, you may need a crossover if you add an amplifier and a subwoofer to that type of system.

Are crossovers necessary?

Why Do You Need A Crossover? Every audio system, including the one in your car, needs a crossover to direct sound to the correct driver. Tweeters, woofers and subs should get high, mid and low frequencies respectively. Every full-range speaker has a crossover network inside.

Is active crossover better than passive?

Passive crossovers don't need power to filter the signal as desired. Active crossovers require power and ground connections, but give you much more flexibility and fine-tuning control over your music.