NEW DEVELOPMENTS IN ELECTROSTATIC LOUDSPEAKERS.

Predicting the performance of a loudspeaker involves a large number of terms, some of which are only known for very simple shapes, and even these are only valid over a restricted frequency range. If a loudspeaker can be constructed with a sufficiently unrestrained and light membrane and with no other baffles or acoustical obstacles so that the whole is effectively acoustically transparent, then it can be shown by reciprocity that the transfer function reduces to a simple expression devoid of all complex and ill-defined impedances. Indeed, the acoustic pressure and phase at any point in free space can be determined from the simple measurement of the electric currents circulating in the trasnducer elements.