Sorry to revive old thread, but i just joined akg only recently.
I agree with the above post, i sheldom listening to musics anymore. k501 sounds really good for movies, tonally very realistic, seductive mids, LLLAAARRGE soundstage.
Now i am looking for used made in Austria akg k702, also for movies.
I too like movie watching using headphone.
My favorites are Sony SA3000, HD800, Sony MA900, Audio Techica AD700, AKG K501. Please note that the list are not in order, i just listen to whichever my mood drives me.
I tried K70x (K702 to be exact), i think it is very nice for movies too. I tried k712, but i think it is too warm for movies.
Depend in what is your definition of improve. To me, k702 lose the warmth and intimate vocals that i like so much about ad700. The added upper midrange emphasize doesn't help either.
But maybe you get more detail out of k702.