since some of your friends have already seen the info on the other site now, i'll ask you because it's already been let out.
have you ever considered energy/time into your incomplete formula's? or any of the other issues involved?
you don't have to answer that to me, i don't care. just think about it your self.
get off the linear travel and volume displacement wagon. those have their place, but there's more factors involved that contribute to increased wave amplitude.
who gives a crap what it looks like in theory, on paper, and on computer "modeling". that's only the beginning of engineering. people should be more concerned with what a speaker is intended for. how it sounds in the real world application. making a top notch speaker is part science, part art.
no DD isn't the answer for every application and it isn't the answer for everyone.
but no one has a leg to stand on to try and argue against the fact that they are the bench mark of engineering and build quality. wether you do or don't understand the how's and why's of the things they do.