Would you like ultra low bass that you can feel as well as hear then you have 2 options 1 using conventional subwoofer and turn the volume up to the pain threshold or 2 use the bass pump iii in comparison with normal speakers the heavy bass pump iii has no membrane instead it is screwed to the bottom of the vehicle this delivers the impact sound felt as the deepest bass directly to the listener so you can experience the music with the intensity of a live show even at moderate vol