The electrostatic loudspeaker is very simple in concept, but difficult to construct successfully in practice. lts operation relies on electrostatic attraction and repulsion, in much the same way as a piece of thin paper attracted to a rubber balloon that is charged by rubbing it against fabric.
The electrically charged ultra-thin conductive film diaphragm is tensioned and placed close between two metal grids. When a high voltage audio signal is applied to the metal grids, the diaphragm moves in response to the signal, moving towards the grid which at that instant is oppositely charged, and away from the grid which has the same charge as the diaphragm. The diaphragm responds in an essentially linear manner, producing sound waves which are a very accurate reproduction of the original sound.