andrzejpw,
My DSP Pro came with the 580s from Headroom. My wife and I tried it out finally after about three months. We watched T2, the Ultimate Edition using the Beyer DT 250-80 and the Senn 580. The sound was great, nice channel separation and imaging. I could tell what direction the action came from and where it eventually went. The bass on both phones was deep, the 250-80 were lower, but not as tight ast the 580. Overall the 580 sounded better, not as dark as the 250-80, more detail. I have not used the DSP Pro with my game consoles, too many wires already.
There are some nice features on the unit. Separate volume, tone, and effects control for each headphone. Different settings, phantom, pro logic, hall, theatre, etc.
This is not to replace your home theatre set-up, but for late night movie sessions, the DSP Pro does it's job admirably.
Regards - reynman