IMHO most affordable, under ~$300 closed cans have some kind of earcup resonance and artifacts. The bad ones are those that affect the midrange in an unpleasant way. The better ones, to their credit are very marginal and I can only detect it when A/B comparing, but its usually there to some extent. I think a lot of those headphone demo-displays have a lot of EQ going on, or the set designer choses songs/sounds that don't excite earcup resonances. The bass is usually so muddy and bloated on those things it just obliterates any other sonic attributes. With most of "those kinds" of headphones, I think midrange resonances/artifacts are really the least of their problems.
The other thing too is first impressions are always just that... a first impression. I have always found headphones (even really good ones) to sound very good when new, during the "honeymoon". Only after a month or so do the weaknesses and deficiencies start to show up.
Edited by kramer5150 - 2/12/13 at 7:22am