An electrostatic speaker is described that includes a curved diaphragm positioned between two electrically conductive plates. According to aspects, the curved diaphragm has an “S-shape” and is configured to electrostatically move between the conductive plates. In particular, the curved diaphragm may generally roll between the two conductive plates so as to move from left to right with respect to ends of the conductive plates and push air in a direction toward ends of the conductive plates, thus generating acoustic output. In some implementations, the configuration of the electrostatic speaker reduces a biasing voltage required for the conductive plates.