They use them as midrange. Only one is the tweeter. The idear behind is that they are faster.
So, are we still talking about the Enzo, or the Double Impacts? On the Double Impact's (and many other of Eric's designs), even though they are identical drivers, they are not all crossed over as tweeters. Only the driver in the center is an actual tweeter...all of the other "tweeters" come on line at 300 Hz, allowing them to function as a midrange, but with a MUCH LOWER moving mass, thus MUCH faster than a traditional midrange...Think electrostatics without the shortcomings...Also, SUPER efficient!
Huh? You are going to have to explain that one to me. The tweeters look like the SB dimple domes. If so, then the FS is 680hz.