Hmm, nothing that I have noticed but I'll use mine more and see, but what I have available for comparison is DT990 which is a rather bass heavy headphone, so I would have noticed if it was lacking. I did "bend" the headband since the initial clamping wasn't enough for a good seal, but after that then there's nothing to complain about. How is your fit?
Well... I would have preferred having the cord at the left side since that is what I'm used to
.
It doesn't clamp much, but it's very comfortable, especially for me since I wear glasses. The cord on the right doesn't bother me.
The comparison I'm making:
http://www.innerfidelity.com/images/LogitechUE6000passive.pdf
vs.
http://www.innerfidelity.com/images/NoontechZoroHD.pdf
The bass should be comparable between them, but my UE6000 doesn't have the weight nor the impact of my Zoro HD. Part of it might be due to the driver in the Zoro being closer to the ear since it's an on-ear, but I don't think that's all.