For what it's worth, I don't think I could A/B WASAPI vs. DirectSound either. I use WASAPI anyways, because, well, why not?
edit: still listening plenty to my new K702s. Man, these things are very, very recording dependent. They're not going to do poorly mastered recordings any favors. And shit, I'm reevaluating my position on the bass yet again...if you're playing material that is demanding bass, the K702 will give it to you. Electronic music sounds surprisingly fantastic on these. These headphones are quite nimble.
edit2: case in point, compare Radiohead's OK Computer to In Rainbows. In Rainbows is awful. OK Computer actually sounds pretty good.
edit3: actually, I can't believe I'd be saying this...I feel like the K702 have maybe a little too much bass (though that could very well be my Maverick Audio biasing things...). I guess that means I'm ready for Stax.
You are a strange man.
And yes, it is painfully obvious how inadequate the mastering quality of most CDs are these days.