Nearly 99.99999% the same headphone. The difference is the color and the detachable cable. So yeah, the K70x is not for those who plan on using voice chat, unless you add another amp to the chain. I can't stress how weak they sound as soon as you move the voice/game knob away from 100% game.
As for soundstage, I've gotten used to the soundstage of various headphones, from small soundstages to huge ones like the AD700 and K701. I don't understand the term artificial and it's use with the K701, but I ONLY use them while gaming with the Mixamp and DH enabled. The huge soundstage sounds just fine, and positional cues are as easy as they can get to discern.
To be honest, I find soundstage to be merely an extra boost in immersion and not important to gaming compared to clarity and positional/directional cues. As long as I can tell in what direction a sound is coming from. I'm fine with a headphone. Those with huge soundstages just helps it feel more natural, not necessarily better. My Creative Aurvana Live has obviously a smaller soundstage, but positional cues are nearly as good. That's mostly what matters.
That being said, you don't want a microscopic soundstage when gaming either, because if it's too small, you won't be able to place in which direction the sounds are coming from exactly. You need a LITTLE bit of soundstage distance. Obviously, the bigger it is, the easier it is to tell where sounds come from. A medium sized soundstage like the CAL or DT770's have is more than enough, and these are closed headphones...
My problem with the DT880 was that the sound with the Mixamp (DH enabled) sounded more like it was shaped like a dome, and you're at the center of the base. Almost no rear depth to them, making them nearly impossible to tell front from rear sounds, to my ears. Good headphones for gaming absolutely need to be more circular (you in the middle) of the soundfield. You need some rear depth. =/ Hard to explain with my stupid description. XD
Edited by Mad Lust Envy - 10/4/10 at 5:48am