Single dynamic headphone drivers tend to distort quite a bit in the deep bass if they have a lot of bass tuned in to begin with. The main problem with the ED8s is that they are (or were) not consistent in their sound with each pair. If you go to e-earphone, for example to audition a pair, it would be best to audition a few pairs and find one with the sound you like best. The Sig Pro and Sig DJ are better value to a degree, but still quite expensive.
I was NOT expecting much from them which goes to show how much pre conceptions can spoil a true 1st experience and having no expectations can be great. I'm a basshead and these were just another expensive "gee these are expensive ..I can say I've tried em"
My 1st experience was at e-earphones and they only had 1 ruthenium when I was there. The other was in Hiroshima. The 2nd time I was ready and they really blew my mind. The depth of the low end was down to audible threshold and 50Hz was able to be tuned to forceful levels. They apparently don't need an amp but don't mind one either. Titanium plated mylar drivers and whatever the hell triple bass port is..and a solid rear end housing...I wouldn't buy them because of the cost but this is a bass can list so they go on.