Rockford

If you feel the beat of a teenager coming around the block, you might thank (or blame) Rockford. The company is a leading designer and marketer of high-performance car audio systems that target drivers who like to crank it up. Rockford distributes car amplifiers, speakers, subwoofers, and accessories under brand names such as Rockford Fosgate, Rockford Acoustic Design, Lightning Audio, and InstallEdge.com (an installation shop supplier). The company's products are sold by major retailers, and Rockford also supplies automakers Nissan and Mitsubishi Motors with audio equipment for installation in their vehicles. Once a manufacturer, Rockford now sources most of its products in Asia.