Alright, so they're basically open back headphones. I was really hoping that number would be closer to 5. Thanks for the info.
Hi, I know I'm replying to an old message, but the sounds leakage to outside isn't that bad IMO. I had to get closed back headphones because my HD 650s were driving fiancee crazy, so I went with TH900s and she hasn't complained since. The sound leakage from outside to inside the headphones is pretty significant though, but if you're listening to music it won't matter.