The Quad ESL - Edelman Collection

The Edelman Collection

A significant contributor to the early history of "condenser speakers" as you can see from the PDF links below:

P.E. Edelman was one of the early researchers in practical "condenser speakers" (electrostatics). As such, his work was looked at by Janszen, Walker and quite a few others over the years. Of historical background interest, you can download PDF files of his six (!) notable patents here: