upon a few hours of testing, it's very clear that HD 598 does have a more in-depth and larger 3d soundstage. the AD700 although has a very large soundstage, that it gives you the sense of width. but the 598 actually goes farther and presents a better depth. i don't know if this is due to their EAR technology, but for gaming, it gives a better sense of depth and distance. and because the 598's mid is so much better, it makes AD700 seem a bit muffled in the mid. for classical and acoustic type of music is like removing a cloud in front of you.
there're also substle cues that are more prominent that AD700 had trouble presenting. on certain jazz tracks, few substle instrument noise/sound were brought out in the background behind your head with the 598, the AD700 wasn't able to do that. oh and i noticed something last night that was also incredible. on this one jazz track i listen to a lot, the sax comes from the left side and piano and other instruments on the right. with the 598, you can actually get the reflected sound from the right ear, kind of like cross feed. it really brings out the reality like the sound is bounced from the left to the right and you're getting the feedback of the room. AMAZING
to sum up the soundstage between the two, AD700 is like listening in a rectangle shaped room with the widest part being the left and right. 598 extends that by adding front and back depth farther.
i'll update on more as i go. but this would be very helpful for anyone who game and listen to music a lot like i do.
Edited by howzz1854 - 10/5/12 at 10:06am