I own the xb1000, and I know why there is mixed reviews on their bass response. If they aren't receiving enough power they have very little bass, eg from my phone I need to eq the bass to maximum, and even then its not huge (not to mention everything else also sounds bad when under powered). When I play them from my PC the bass is pretty good, when I hook them up to my amp I can literally feel my brain vibrating, the xb1000 without a doubt have the potential to be the bassiest (clean defined bass) cans in existence when powered properly. Also I did a mod where I removed the felt material from behind the driver aind also from the air opening on the cups, wow just wow, they became about 5x better all the audio spectrum became clearer, sounded like going from $200 phones to $600 phones, no joke, and I've owned my share of expensive phones, so I'm not exaggerating