I now have both D2 and 616 which I assume is same SQ as 818.
I am using Shure e4c for headphone.
Although, I have no idea how to calibrate EQ well, I have been playing around with EQ settings / BSEE / etc... on both units.
So far, they both sound well but it seems D2's sound feel better in my head. D2 fills my head more (Does it mean soundstage?) Sony's sound is concentrated near ears while D2 is just spreading around my head. (is there way to set sony wide like...