Electrostatic speaker

Electrostatic speakers use a thin flat diaphragm usually consisting of a plastic sheet impregnated with a conductive materical such as graphite sandwiched between two grids, with a small air gap between the diaphragm and grids. The grids are charged to a high voltage. The voltage difference between the front and rear grids is modulated with the signal from an audio amplifer stepped up through a transformer. The variations in the voltage cause the diaphragm to move forwards and backwards, thus creating audible sound.

Advantages include very fast transient response due to the extreme light weight o the diaphragm.

Disadvantages include a lack of bass response due to phase cancellation from a lack of enclosure, and a sensetivity to ambient humidity levels.

Current manufactuers include Martin Logan.

There are active experimenters creating their own electrostatic speakers.