Here's what Beyerdynamic gave me after adding their velvet pads originally made for the DT770.
The third or fourth position give the smoothest performance, but not the flattest. Hoping for tighter(faster) sounding bass, I chose to EQ the third position. Decreasing the work your amp has to do never sounds like a bad idea to me. So I got to electronically reduce the bass and let the physics of the alignment do the work. Here's how it turned out for my subjectively flat setting updated 05/08/13:
This one requires more filters than my previous attempts, but the sound is worth the effort even if it's not perfect yet.
1st filter: 60Hz -12dB Bandwidth: 2.54
2nd filter: 141Hz 5dB Bandwidth: 0.48
3rd filter: 250Hz 6dB Bandwidth: 1.39
4th filter: 1000Hz 2dB Bandwidth: 1.39
5th filter: 1340Hz -2dB Bandwidth: 0.43
6th filter: 2300Hz -3dB Bandwidth: 0.64
7th filter: 8400Hz -9dB Bandwidth: 0.71