Basic Electrostatic Principle: The underlying theory of electrostatic speakers couldn't be more simple. The laws of physics teach that "like" electrical charges repel one-another and "unlike" electrical charges attract one-another.
Constructing an electrostatic panel: Using this principle, let's construct a conceptual electrostatic speaker. First, let's stretch a thin plastic membrane on a rigid frame. Then, let's coat it with a low-mass electrically-conductive substance. Next, we fabricate two stiff, flat electrodes, called "stators". They are electrically insulated to prevent electrical discharge. We give each stator the same area as the membrane and place one on either side of it such that the membrane is placed exactly equidistant between the two stators. Finally, the stators must have holes in them to permit sound to pass through. We now have a conceptual electrostatic speaker panel.
Bias power supply: In order for our simplified electrostatic panel to produce sound, an electrical charge must be placed onto the membrane. In our example a positive charge is used.
Step-up audio transformer: The audio signal voltage from an amplifier is connected to the two stators via a step-up audio transformer such that the signal applied to each stator is identical with the exception of phase, one signal is 180 degrees out of phase with the other.
Why it works: Thus, as the signal voltage on one stator increases positively, it repels the positive charge on the membrane. The signal voltage on the other stator is increasing negatively and, hence, attracts the positive charge on the membrane. The result is that a "push-pull" force is exerted on the membrane. When the audio signal reverses, the push-pull force also reverses. Since the membrane is compliant, the push-pull electrostatic force applied to it causes it to move.
Finale: Consequently, air is moved and sound is created in the image of the electrical driving force, doing so with extremely low moving mass and with maximum membrane control. For those who would like further information please press the "white paper" button below.