Cone breakup resonances are another matter altogether. I believe all the big drivers have some past 800 Hz or thereabouts, so it's more a matter of how bad are they and which sound least offensive. There can be a lot of sound still coming off the cone after the event is over because the cone is ringing like a bell at certain frequencies. You can cross it over or EQ it all you want, but it can still quack like a duck if the driver is spikey up high. I heard a frat party system once that had a hot 18 crossed to a small 3500 hz horn. Didn't matter what the instrument was, handclap - quack!, Snare - Quack!!, saxophone - QUACCKKK!!, you get my drift. Most frequency plots are set so the "pen" moves too slow to show how bad breakup really is, so you just have to be a carefull shopper and find designers/posters you trust (guess your in the right place already).

Thomas