Aren't you also returning them in the first place though, to get the fixed non-defective rev2 HE400s?
Anyway regardless, it just sounds like there is too much clamp, which is easy to fix - hold the two corners of the headband with your two hands, stretch/bend until the headband is completely flat, hold it like that for like a minute, and voila. I don't see why you're having trouble with that at all.
I already did that... I've left them stretched out on a pillow for the past hour or so, maybe they'll be better now. What's hard is that I'm not sure if it's my HD600s or the HE400s causing it, to be honest. The HD600s don't make me feel like I have a ring around my ears, but they go on the same spot that the HE400s do and I've worn the HD600s a lot longer since I got them than I have the HE400s.
Edit: Okay, I flattened them out even more, gripping the mounts that say HE-400 and specifically bending those flatter. They're certainly much less clampy now. I'm leaving my HD600s on the pillow for now, as I think those are tighter. I would love them even more if they weren't as tight as they are. It's not awful but it could definitely be improved. The only problem I have with the HE400s and the way you can position them is that some positions, though more comfortable, don't complete a seal around my ears. They do feel better after stretching them out, though. I'd love to mod the headband with a Beyer pad or something. Would make them even better. I want to try and work in the velour pads so they get squishier. They're pretty stiff as it is right now.
Edited by yokken - 10/7/12 at 12:24pm