I had the K702 and I had two minor issues with it. It's my most purchased headphone. I've went through 1 K701 and about 3-4 K702s. A bit obsessive you could say. I kept coming back to it despite some issues I had with it. The K702's treble always bothered me. Then the soundstage seemed almost phony and artificially huge. This is what killed it for me in gaming. Just not very accurate at all. The treble was the #1 (and only) reason I got rid of my last pair. Very fatiguing.
Got the Q701 recently and loved it immediately. The issues I had with the K702 are GONE. Is it my imagination? Maybe, but I don't care. People can say there is no difference all they want, but I just know I love the Q701 and the K702 still has the issues that bothered me. Maybe it's variations between drivers. Nothing on my end has changed. The K702 had 100+ hours of burn-in.
The differences to me are extremely minor. It wouldn't be worth it for someone to upgrade from the K702 to the Q701. My ears DO in fact hear much smoother treble. Could it be that AKG burns them in longer at the factory? Who knows. I've listened to the Q701 a ton and the treble doesn't bother me. The soundstage also seems a bit smaller and more accurate. Don't know why. It's especially noticeable with games.
There's now 2-3 people out there who prefer the Q701 (but not the K702) over the K501. You could say I'm one of these people. Weird huh?
The Q701 also seems a lot warmer than my old K702. I never remember the K702 being all that warm, so this is strange. No amp change or anything. Of course not as warm sounding as the K702, but close. IMO the Q701 isn't thin sounding at all, not even close.
Since buying the Q701 it hasn't crossed my mind at all if I should sell it or return it. I like it that much. Vocals don't randomly sound distant due to the goofy soundstage. It of course depends on the recording itself. Right now the mids certainly don't feel forward, just the upper mids a bit. Usually if the song bores me with the Q701, it's just the recording.
Again..any difference are extremely minor. I think it's enough of a change for me to finally keep them for good now.
BTW that small button on the grill could play a huge role in how it sounds. I have my doubts if they just slapped a button on there for no reason.
Now theres a few people out there who compared them side by side and haven't heard a difference. Best to just compare them yourself.
I do not hear more bass. Could still be a tiny bit, but I'm not hearing it. Biggest difference is the treble and what seems like a slightly smaller and more accurate soundstage.
Edited by tdockweiler - 11/7/11 at 4:33pm