Definitions for "Electrostatic Speaker"
a dipole speaker for example
A loudspeaker that uses a large, flat (sometimes curved), thin membrane instead of a cone. The membrane is situated between two screens that are charged with a high electrical voltage to move the membrane. Ideally the entire membrane moves back and forth as a unit. The large area and low moving mass are advantages. The limited membrane travel seriously limits the low frequency response. Also presents a difficult load impedance to an amplifier.
One of the oldest speaker design principles, electrostatic speakers are generally comprised of two fixed perforated panels with a constant high-voltage charge applied to them. In between these two panels is an extremely low-mass diaphragm to which the audio signal is applied, causing it to move. There are variations on this construction, but all electrostatic speakers are free from the magnets and voice coils used in conventional speakers.