Actually one of the problems with the K701 is how the headphones are wired. Recabling them directly to the right and left drivers opens up the frequency extension on both ends. As stated before, they are a bitch to drive (ala K340 bitchiness) and definitely suffer in the midrange when underdriven. However, recabled and edequately powered (balanced definately helps) I consider them keepers. My pair is a fairly low serial number, so keep that in mind. I also did not notice much burn-in effect on these phones. I need to get a pair of HD800's to be absolutely sure, but my current impression is that the closest phone I have heard to the HD800 is my K701, but I think the K701 trumps it in the midrange.