Audio Wiring / September 5, 2018 / Raquel Dufour.
Route the power cable from the battery through the passenger side of the car to the amplifier in the trunk. It will prove most natural because the battery is commonly on the passenger’s side of the vehicle. You will have to feed the power cable through a rubber grommet on the firewall.
Route the signal cables (RCA cables) on the driver’s side of the car from the head unit to the amplifier. Ground the amplifier to a clean metal surface on the car’s chassis. The ground should be no more than 18 inches from the speaker. The ground cable must be the same gauge size as the power cable used.
You don’t want to route signal wire next to power wire because that could result in noise entering the sound system. If power cable and signal cable must cross, cross them perpendicularly. Use well-shielded RCA cable. It will help prevent noise from entering the sound system. Ground the radio to the chassis. Connect the antenna to the proper antenna input on the radio.
Not every car audio crossover operates in the same fashion. Crossovers vary as to the number of frequencies sent to other components of the car audio system. Crossovers also vary as to the rate at which the wavelengths are attenuated or cut. This rate, however, is not fixed. The owner of a car audio system can adjust the speed about which the crossover attenuates or cuts the frequencies that become fed into the power amplifier.