Krutsch
Headphoneus Supremus
DavidA is correct. You have to find your Dac and then your Headphone Amp. (Try to go to a Can Jam or local Audio Shop so you can sample different combos together) Once you find your combo (and you will know it when you do) stick with it and enjoy.
I have Sonarworks and I use the Average for the HD700's and (for me) the Sonarworks takes that edge off and gives an even better soundstage.
Also as DavidA stated those HD 700's love to be driven by a Tube Headphone Amp (or hybrid) I agree as many others who post here. I also have the Asgard 2 and it just doesn't get those HD700's where they need to be.
I changed my cable to a Moon Audio Black dragon v2 and for me that worked wonders (I know many out there don't hear a difference with an upgraded cable or believe in upgraded cables and that's fine)
See below for my best combo for my HD700's (I do have upgraded Tubes as well)
Behold! The bottom D-getter equipped WE421a. Nice glass, guy!