My only problem with the Ultrasone Pro 900 is that like every other Ultrasone can I've tried, they tend to hurt the top of my skull after about an hour or two because the measly little pad on the headband manages to somehow rest the entire weight of the headphones right on the dome of the skull. I had a set of HFI-680 some 3 years ago, so I knew what I was getting into when I ordered the Pro 900 - but this time I had a plan...
What you'll need:
1 pair of Ultrasone full-size headphones - You probably already have those, since you're reading this.
Velcro (2x10cm, both the soft and the rough side) - Visit your local crafts store. Make sure you get the stuff with adhesive backing.
1 Sennheiser spare part #088597 - Google is your friend. I live in Denmark and got it from Germany, just search for that specific Sennheiser part number and find a seller close to you.
First, peel of the standard pad. It's glued in place, but with a dull knife you'll be able to loosen one of the corners of the pad, then it just peels right off. That should leave your Ultrasone headband with a small recess like this:
Fill that with the soft part of the velcro:
Then you add the rough piece of velcro to the back side of the Sennheiser headband pad:
And then it's just a matter of placing the padding on the headband:
A total effort of about 15 minutes of work, after I figured out the best way of doing it. The mod is VERY easily reversed or you could experiment with different kinds of padding - now you just have to add velcro to whatever padding your want to try and slap it on your Ultrasones. The Sennheiser pad is A LOT more comfortable than the stock pad!
Edit: JayKay reported that for you guys in the US, the easiest and cheapest way to get the HD650 pad is to call Sennheiser and order that specific part number (088597). The lucky bastard even got it much cheaper than what I paid in Germany!
Edited by Sorensiim - 11/28/11 at 11:16pm