Most factory sound systems can't give you the dramatic and high quality bass range that comes from having a subwoofer. Achieving the bass tone you want depends on power, space, enclosure, sensitivity, impedance, and number of voice coils. You can pair your subwoofer with an amp or purchase a subwoofer with an amp built in so that it's already powered. The bass from your subs will create the sound and feel of a live show happening in your car.