I have a pair of Beyer DT990 velours on my AKG K240 Studios at the moment; an interesting change over from the stock pleather.
-The infamous Beyer pads and the AKG K240s are the perfect combination for comfort. The ultra light and lightly clamping K240 is converted to the preferable circum-aural style. (Mickey mouse ears like mine will contact the driver enclosure with these pads, which may be an issue for some.)
-Soundstage is more spacious and precise.
-Highs have more sparkle, without piercing any eardrums.
-Bass reduction cleans up mids.
-NOBASS. I might try the DT770 pads next as the DT990 pads limit the K240s to genres of music that don't ask for neutral to emphasized bass. I've never heard the AD700X but from the descriptions I've read I imagine that the K240s w/ DT990 pads have a similar bass roll-off.
-These pads are 8/10 on a scale of difficulty to install. They do fit the K240s without modification, but it will take you a good 10-20 minutes of stretching and probably an extra pair of hands to hold the pads stretched while you flip the attachment ring(?) over the rim of the cup.
I'm going to be keeping the DT990 pads on my K240s, at least until my DT880s arrive:) I was craving an airier-than-my-MadDogs experience and this definitely gave it to me. The bass roll-off is frustrating with some tracks but it's brought me to new, fun flavors of head-fi, on the cheap:)
The K240s came for $15 by way of craiglist, needing a solder job to the connection in the right-side cup. If you're browsing this forum and you don't own a soldering iron you are doing it wrong. These almost made me regret shelling out $300 for my MDs(not really).
Edited by Roarkish - 9/3/13 at 11:09pm