Car speakers like Rockford Fosgate Prime 6.5″ Coaxial Speaker, JBL Premium 6.5-Inch Co-Axial Speaker, Pyle 6.5-Inch Mid Bass Speaker System, and Pioneer G-Series have the best Bass. The easiest way to increase the Bass in your car is to utilize physical controls on the side of your car radio to increase the Bass and decrease the treble. Set up a subwoofer.