I have the AD900X, A900X and the AD500X. I love the 3D wing design on these, plays nice with the hair (what's left, lol). I sure do wish all my headphones had this design. The AD900X is super light (unlike the A900X) Only thing I don't like about the design of these headphones is that the cable is not removable. For the sale price, not a terrible deal although the headphone isn't really anything special.
The AD700X is probably the more popular headphone for FPS gaming, the AD900X has an increase in bass at the cost of some clarity. The bass really isn't one of the strengths of this headphone, there is enough there to keep everything from sounding flat and deflated. I do love the AD900X for general gaming. It has a generous soundstage much like the X2HR which really helps you to get into the game.
Between the AD900X and X2HR, I'd much rather use the X2HR. The X2HR has all the same strengths but way better bass which makes for a more engaging experience for me in both music playback and gaming. I do come back to the AD900x often because the wing design plays nice with my hair and is still a competent headphone to listen to music. I liked the design so much I picked up a AD500X for the office.
RamboneAD900X's clarity isn't intruded upon by the bass in the slightest, unlike your claim. Bass is too weak for that, as you yourself can hear. The Sennheiser HD25 is an example of a headphone whose bass actually intrudes into the upper frequencies. It's the lack of perforations on the inner side of the earpads that hurts clarity and gives AD900X a boxy sound. AD900X needs bass boost, if anything. The original AD900 (non-x) had perforated earpads. Cutting small holes into AD900X pads unleashes clarity and helps open up the sound. Pictures of Beyerdynamic DT880 earpads will give you the idea. Easy to find via Google.
Valensilius_ZephyrusJust my impression vs the AD700X, not that the bass is all that impressive on the AD900X to begin with and when I mean loss of clarity, I mean really miniscule but it should be noted if I had to find something to nitpick. No doubt the AD900X can be improved through pad swaps, alterations or EQ but I moved on from the AD series long ago to the Philips Fidelio X2HR. The X2HR felt like an upgrade in almost every way right out of the box while keeping the same sound stage. The X2HR I've come to learn can sound wildly different from ear to ear. I've looong since moved on from the X2HR and am rocking the Hifiman Edition XS at this point which I feel is a direct upgrade from there. The bass is pretty damn good with an iFi single Xbass or double Xbass boost.