The k702s are okay imo... with EQ. Very lean presentation that's lacking bass and mids presence. The soundstage is also unnaturally big.
i find the bass on the 702 fine and has very good punch. just what annoyed me about them is the sound starts to fall apart when you crank them up. you can hear the cloudiness/distortion starting to rise very quickly. i never found the k702's too hard to drive and sounded loud enough out my phone or ipod. speaker amps made little to no difference to me.
the mids bothered me when i first got them too cause coming from sextetts lp and DF's, the midrange sounded really off to me and not nearly as good. still find my sextetts lp and df's overall better headphone to the 702's but do like the 702's good bit. they do sound really smooth/clean.
the big openness though i did find tad weird but actually liked it which made it such a good to near perfect low level listening headphone.