Ok, good to know, thanks. After you told me to consider the DX1000 as a TH-600 replacement, I can't get it out of my head. Even after getting the NightHawk. I've yet to find cans that have authoritative bass, natural mids, and smooth / slightly rolled-off treble that also has a big enough sound stage. TH-600 misses 2 of 4 (mids, treble), HD650 is missing 1 (bass), and so is the NH (sound stage). I need to try these JVC so I can know for sure if it fits the bill.
How funny, I'm looking for the exact sound signature. I thought it was weird to want a sound like that, but good to see I'm not alone. The closest I have been able to get to that sound is the M- audio q40 (while eq'ing down the treble). I have the dx1k on order I think (first time I tried bank thought it was fraud and stopped transaction. We'll see how the 2nd attempt goes). I'll let you know if they are the unicorn we are looking for friend.