An electromechanically actuated electret-based loudspeaker made with an organic material membrane is presented, which is small in volume, extremely thin, and lightweight for light vehicle applications. As obtaining good sound quality in a vehicle is a complicated and difficult task, the electrostatic thin-film actuator can be cut into any shape and then assembled into an electret-based loudspeaker for placement at any location within the vehicle. The sound field in a vehicle can be optimized by properly tailoring the electret-based loudspeaker performance and choosing the most appropriate location for the loudspeaker for optimal sound performance. In addition, it is possible to design a novel 3-D sound field. Our newly fabricated 100-mm-by-100-mm electret loudspeaker weighs only 4 g and is 1 mm thick. It only consumes 0.15 mW to generate a sound pressure level at 88 dB at 1 kHz, which is very energy efficient for electric car applications. In summary, our newly flexible electret-based loudspeaker has tremendous potential for future automotive applications due to its excellent advantages over current vehicle loudspeakers.