It pretty much only gets rid of that one 'razor of death'. The null in the original is really just an artifact so the change in FR isn't quite as impressive as it seems.
Personally, even without the mods I love it. I'd probably take it over any full size dynamic/ortho rig I've ever had the chance to hear. Mostly because it has much better instrument separation.
I think the severity of the ringing it shows is in the first CSD an artifact also. I could certainly hear it beforehand but it didn't sound that bad. I know the FR on those Lambdas never measure right on normal couplers though. I think you have to have a HATs, or something. On my head at least, they sound like the FR graph that Tyll has on IF, without the bass roll-off and rivaling neo-orthos in bass extension. The Lambdas on Ryu's site do a similar thing with a bass hump followed by a quick roll off. Tyll's numbers show that's probably a fit/seal issue.
OTOH the ringing might be real. The CSD is a lot different from purrin's (even accounting for his secret sauce algorithms since I've got results approximating his with other 'phones) but the 'phones themselves might be different too. I said "mostly stock" but since they're pretty old so I don't know if they had the same kind of pads. I also had to remove all factory foam and fiberglass from the cups since it was crumbling. They aren't completely stock.
I did some more messing around after I posted those graphs yesterday and found something interesting. I was trying to get rid of the hash in the CSD around 2K or so and tried adding damping to the back of driver to see what it would do It helped a little with that but it also moved the ~8khz-ish ringing that the foam and felt had killed up to about 14 or 15khz complete with a null in the FR. There appears to be a pretty interesting relationship between the driver and the ear side of the enclosure.
I listened to it for a while like that and it sounded pretty good with most stuff. Even cymbals normally didn't seem to excite it too much. Then I put on some Yuki Kajiura OSTs which are my usual torture test for this kind of thing since she uses tons of bells and chimes. It was noticeable at low-ish volumes and fairly annoying at higher volumes so I've got some more work to do.
Hopefully I'll be able to either damp the driver until the ringing is completely out of the audible range without messing up anything else or find a material that will take care of it on the ear side.
