Ah... might as well upload them all:

Ultrasone Pro750 (above) not even measuring that bad, no idea how it sounds.

I can confirm that these aren't awful; their highs are actually reasonable, as is the bass, but the mids have this polarizng thing about them that eventually made me stop using them in favor of the 840's.

Just bought me a pair of these for fun that should arrive any day soon. If they are bassy and have a tiny bit of the soundstage that some people say that they have, I will probably be happy. No clue what to think of about the midrage after seeing the CSDs though. Looks, uh...

The Pro750 was my first higher-end headphone since buying the M50 as a gateway to Head-fi.  My first was actually the Sony CD3000 years ago. Did lots of mods to the 750 and learned a lot reading about the Kees mods.  My biggest issues were the irritating pads that scratched and poked me w/ the worst fabric i could imagine being placed against human skin and the plasticky snares and upper mids.  I think they had an overstock.com deal for $175 at the time.

Years ago I grabbed a defective Pro750 that I fixed up by snipping the diodes out. As basshead cans go, not bad. Not the cleanest by any means, but very visceral and didn't bloat over the lower mids like other bassy cans. The whole soundstage/mids thing was weird though. Not particularly shouty, but it was kinda boxy feeling, like I was in a small empty room. Made some things feel extra wide, but others hollow. I don't recall anything particularly offensive in the highs.

A really small cavern  Something like the Audio Technica A700 feels cavernous to me.

Well, from memory the HFI series weren't quite as bad as the pro series. But I have less experience with those models and my memory is fuzzy on them now. I had an HFI450 briefly, but wound up shoving an ortho driver in there. Don't even remember which one... might have been an SFI.

I think the Signature Pro/DJ are built off the HFI chassis aren't they?