If you want bass from a given box and driver, you have to reduce sensitivity. if you want efficiency, you lose bass, if you want both, you need BIG boxes.. The "E" series were an attempt at efficiency-first, so you get not very much bass, a screaming mid and rather agressive treble. Suitably matched, these can be enormous fun, but get 'em wrongly matched or set up, and you'll get hearing damage
I can't go on and I can't go back, I don't feel so matter of fact,
I tried and tried to make good sense, What's the good to try it all again?