Summary: I am new to headfi and this is my second review. I apologize if its not very helpful.
These entry level cans from sennheiser give a good taste of their higher end models have in store. First how they sound.
These have very good mid range. Nice lush and full. Treble is slightly rolled off, giving them dark sound signature and slight sennheiser veil. It is present and clear but does not have any sparkle. This gives them a dark sound signature.
Summary: after a few days of using it i found that the bass somehow gets a lot better compared to how it used to be out of the box. But for really low bass frequencies which tend to vibrate the membranes wildly, it affects the highs and mids. Imagine talking in front of an electric fan where your voice gets cut and distorted. I like the bass though it's... honest since I listen to rock and ambient music most of the time.
Pros: Overall sound quality is awesome. honest bass (not boomy but really good)
Cons: Not too compatible with most portable mp3 players. requires headphone amplifiers.
Summary: I won't pretend I know a lot about headphone quality and such; I'm 15 and I've only cared about music for a year or two. These are also my first pair of decent headphones, I love them. They sound crisp and they're bassy without being too much so. I can hear things I never noticed before in songs I know really well. I've tried them with rock (classic, punk, soft, hard, acoustic, baroque, progressive, psychadelic, alternative, surf, gothic etc. etc.
Pros: Sound quality, comfortable, minimal leakage
Cons: Blister packaging, quiet with portable music players