German-Physiks (makers of the DDD "Walsh-Driver" say this about the Heil; "... leaf transducers which include all electrostatics as well as ribbon type dynamic loudspeakers; flat panel speakers such as the NXT and BEST; the Heil air motion transformer which is essentially a class with only one member."

Albert Von Schweikert says on his website "...Albert worked closely with Dr. Oscar Heil, inventor of the Heil Air Motion Transformer (a folded-ribbon tweeter with some of the finest measurements ever recorded)."

So it appears to be thought well of. Now knowing vertical dispesrion is extremely low and the diaphram is essentially a horn loaded ribbon (front & back) with a very wide horizontal dispertion pattern, do you have any other thought about using 4-8 per side?

Thanks, Tom Scata (thetubeguy1954)