Deep and wide are two different things. I'm sticking by what I said, they are not key term "wider" (bigger) than the AD700, having played with both stock and modded. The AD700 sounds light compared to the heavy sound of the K550 which is why you perceive in them offering a bigger soundstage. Given that the K550 are no slouch and I thoroughly enjoyed one when I listened to it. The downsight is the annoyingly bright sig of the AD700 and no bass, not even tight or punchy there is hardly any bass presence on them.
The AD900 is a worlds apart upgrade from them. AD2000 even bigger, the AD1000 is rubbish on the other hand, disappointment mess by AT.