If you're looking to improve the sound quality of your car's subwoofer, there are a few things you can do. First, make sure that the subwoofer is properly installed and secured. A loose or poorly-installed subwoofer can cause rattling and other issues. Second, use an equalizer to adjust the sound levels of your subwoofer. This will allow you to get the most out of your subwoofer and ensure that it sounds its best. Finally, keep your subwoofer clean and free of dirt and dust. Regular maintenance will help to prolong the life of your subwoofer and keep it sounding its best.