However, this post isn't about the earpad change. This is about making this a virtually angled driver headphone.
First step for this mod was buying some 10mm thick padding foam. Make sure you have at least enough to cut a circle with a diameter of 100mm from it. Preferably more, in case you aren't satisfied with the first cut.
Next step is to actually cut said circle out of the foam. To do this as neatly as possible, I printed a template I drew in Illustrator.
Then, I cut the circle in half and cut out two 70mm inner circle parts (see template). Thus leaving two foam 'half moons', by lack of a better description.
With these 'half moons' cut, carefully taper the ends of both halves. This way, you'll have two halves that are 10mm in the middle and gradually get shallower towards the ends. Like this, basically, although it couldn't have hurt to cut a little neater. Oh well...
Now it's time to put these foam 'half moons' under the earpads as neatly as you can. Make sure one end aligns with the pivot points and the other end aligns with the cable entry points (the cable only really enters one earcup, but there's this very noticeable flat part in the other cup). If you do this correctly, the foam will lie back about ~5-10mm from the inner edges of the earpads. This way, there should be more than enough room for your ears never to touch the foam.
Now the ATH-AD900 has virtually angled drivers. Of course, it's actually the stuffed earpads that angle the drivers, roughly aligning the drivers with your ears. Looked at from the bottom, this is what it looks like. What this mod does is make the headphone more comfortable, for your ears won't touch the drivers anymore. I had hoped the leather pads themselves would be thick enough to solve this, but this turned out to be false hope.
I have tried the phat pad mod (stuffing rubber tubes underneath the earpads and thus distancing your ears from the drivers) before. It works well with the stock velours earpads, provided you choose thin enough tubes. But for me that mod didn't work well with the leather earpads. It made the highs a bit too shrill to my liking and the sound was too flat, in my opinion. This led me to try and mod the AD900 differently. This was the result. As an added bonus, I feel that the mids (and thus vocals) almost fully recover the intimacy that's lost from going from the velours to the leather earpads. Try it if you like. If so, report back about how it works out for you. I'd love to hear from you!
EDIT: By the way, I also tried a double mod, with two pieces of foam in both drivers, on top of each other. While further angling the drivers relative to my ears, it sounded awful. Highs were awfully shrill and the vocals went flat. All life was sucked out of the sound, basically. So if you try this mod, you'll definitely want to choose thin enough foam. Start with 10mm thickness, as I did. You can always go thicker if you want. It would be interesting to try this with the velours pads. I haven't tried it, and am probably not going to either. I already love my AD900 too much like this.
Edited by Bengt77 - 9/21/11 at 2:54am