The word ”Pistonic” has its origins in the way the diaphragms have been developed. The diaphragm is a composition of two very different materials, each having their special mechanical properties. One material for the piston area and another material for the surround.
The piston material must be as stiff and lightweight as possible at any given frequency in the passband and the surround- material on the other hand must be as soft and flexible as possible allowing a very large and linear vertical stroke.
These material properties will ensure optimal signal handling over the full frequency range specified and thereby a crystal clear sound reproduction.