Yeah, having heard some of them before, I don't think any of Audio-Technica's lineup is going to have comparable bass to the HE-500. If you like the Fostex TH-X00's then I would consider upgrading to a TH-610, I owned a pair of Lawton modded TH-600's and they were awesome! But the new TH-610 / TH-900 mk2 already include Lawton's driver modifications so the only real benefit would be the deeper wood cups. Either way, the quest for a resolving closed-back with proper bass response really is difficult isn't it? You think so? What makes you say that? I've owned LA600's (Lawton Modded TH-600's) in the past and really enjoyed them, but they were a bit too muddy for me. But man, that bass response was sweet. I always forget that the JVC DX1000's exist, but maybe I will give them a shot. I'll go poke around and see what some of the older reviews have to say.