One thing that is good about the 2426 is that response is a straight diagonal line. That makes a complementary slope possible to provide a flat response curve. There isn't quite enough there with passive EQ, and the collapsing DI of a tractrix or exponential horn doesn't do it either. But both methods increase top octave response, and in any case, it's a nice straight line with well behaved breakup.Other compression drivers with more HF energy sometimes have multiple peaks and valleys. If the dips and peaks aren't too large, then the added energy up high might be worth it. But you can't EQ that kind of behavior away.