nvm i will go to kelisa house for long long time to listen. no worry.
=P of course, IF he allowing me to go. hahha

here's interesting things i found in internet about K701
first i were wondering, how they manage to make a diaphragm sounds so even in all frequency, as we know the physical characteristic of the plastic / mylar / watever membrane has a nod point... =P
but hell they are cleaver to make the diaphragm into different thickness to eliminate the sound resonance problems, and increase accuracy. not sure about other brand though. but this really impressed me. even though i haven't heard it. and i am quite a noob in physics..
and this really deserve a huge successfull. rather than just blindly upgrade the magnet gauss and decrease the voice coil weight / changing in membrane material and then slap in a new model then selling it higher price.

as far as i remember, HD650 has a driver which has a big hole in the middle, hence the air pressure is balance, membrane can vibrate faster. and the duofole to increase the rigidity of the membrane... cool things.

The more you look at the pages of K701 review, the more poisoned you will get. Get off of it. =)