JanZen z87 panel construction
These unique electrostatic transducers achieve wide dispersion and high sound pressure levels without the sonic compromises required by curvature and facets.
Each is split electrically down the vertical center. In the standard configuration, the entire area gets the midrange signal, and only half gets treble. In this way, treble dispersion is increased so that it overlaps the midrange dispersion.
This eliminates beaming and at the same time eliminates the need for a rolloff network to reduce the naturally rising high frequency response. The rise happens naturally when all energy is going into making sound, and none into accelerating mass.
They are 8" tall x 7" wide (hence the z87 designation), with an active area of 39.5 square inches [255 square cm].
The zA2.1 has two of these panels in a single column, hence the 2.1.