Honestly I've heard all 3 numerous times, and I own both that Shure and the AKG which I'm listening to right now. I'd say the mids and highs are dead on for that graph, but the bass on the SRH440 had to have been measured incorrectly both because innerfidelity's graph doesn't agree with headroom's SRH440 graph at all and also because I know for a fact that A/Bing them you can hear a much more balanced bass response on the SRH440 with more sub-bass present. Either that, or the midbass is so overwhelming on the 240 that I hardly notice the sub-bass. That is probably more likely. The M50s are definitely like that, slow sloppy midbass and they also have a weird flat-ish peak around 2k in the midrange making distorted guitars sound strangely unnatural compared to actually being in front of those amps (I've played metal guitar for over 10 years now). Lastly it is painfully evident the extra treble spike on that graph in the 240s. The more you listen to them the more you get used to it though. It's happening to me right now...lol
The soundstage is far better on the K240s than either of these headphones though, as it should be.
Just some thoughts from my end, from personal experience with all 3 cans. It's always fun to compare impressions with you guys since we all hear differently.