I strongly question Oratory1990 measurements. They differ strongly from ones on rtings.com. For what I hear on HD600 I believe rtings.com measurements are more correct.Those EQ settings look very strange to me. A -5dB cut above 13kHz is a sure way to make the HD600 sound rolled and lifeless of any air IMO!
I made a mild EQ based on rtings.com measurements and listening which I feel neutralizes HD600 a lot without adding Harman response bass boost:
1: high shelf 40Hz -5dB Q=0.65
2: high shelf 250Hz 1.8dB Q=1
3: high shelf 870Hz -1.8dB Q=0.71
4: PEQ 3150Hz -1.4dB Q=2.3
5: PEQ 5700Hz 3.5dB Q=2.3
My ears say Oratory1990 filter isn't neutral in comparison.