From Jim Thiel in Soundstage review of 2.4SE
http://www.soundstageultra.com/equipment/thiel_cs24se.htm
How were the improvements measured? Jim Thiel again: "The improved resolution is not the kind of thing that shows up well in measurements; the magnitude of the difference between the CS2.4 and the CS2.4SE is more easily heard than discerned from graphs. The new capacitors allow more nuance, air, detail, and decay to be reproduced by the coaxial drive unit. This was especially evident to us when listening to recordings that contained realistic reverberation, as well as recordings where the instruments were not processed heavily."
http://www.soundstageultra.com/equipment/thiel_cs24se.htm
How were the improvements measured? Jim Thiel again: "The improved resolution is not the kind of thing that shows up well in measurements; the magnitude of the difference between the CS2.4 and the CS2.4SE is more easily heard than discerned from graphs. The new capacitors allow more nuance, air, detail, and decay to be reproduced by the coaxial drive unit. This was especially evident to us when listening to recordings that contained realistic reverberation, as well as recordings where the instruments were not processed heavily."