I also use wired Sennheisers. I can't believe you use open back, though! I have Sennheiser HDsomething open back for music and they are mind blowing. I use closed for gaming as the open back lets every little external sound through. You must have a very quiet room.
I remember one time I was using the open backs for a game, I kept looking around (in game) to see where the rain was falling. Turns out, it was just the rain (light sprinkling) in real life and I could hear it perfectly clearly despite the headphones.