The impedance curve is neglectable for the simple transducers used in headphones -- if you amp them properly. Resonance, cup construction etc. can all be subsumed under either frequency response or fit. How do we hear things like resonance? We can hear it only so far as it does change the frequency response. If this change is "subjectively" related to the particular shape of our ear, it's caused by the relation between the headphone and our ear, thus by the fit
They are - just like all analytical sounding headphones - very well suited to jazz and classical and a little less well suited to rock. However, they can be made perfectly suitable for rock music, if you have a good EQ at hands.
Edited by timar - 6/14/10 at 12:10pm