After only having my xbox 3 months I decided to splash out on these headphones, the instruction book is quite frankly bloody awful so here's how to cut down on the frustration, the toslink connections are a bit iffy, they look like they should push and click in both the control box and xbox, but they dont.
and if your wondering were the hell the the toslink connection on your xbox is its a small black port on the back of the AV cable that connects it to your tv. after finding all this out the hard way all i got was a loud hissing noise from the headset, until after 20 mins and 4 glasses of wine I wiggled the connection in the back of the xbox and then KABOOM! these babies came online.
They are amazing, Im normally a pc gamer and have some speedlink medusa headphones, these pee all over them, the sound is crisp and clear the bass makes the side of your head vibrate. There are people that say you can't hear voices on xbox live unless you set the audio output on your xbox to stereo, not strictly true you can get a good balance on 5.1 it takes patience and some fiddling with the seperate volumes. the mic is very good but quite sensitive.
There are a lot of different switches for time delay on the control box and a lot of other crap I dont understand, but the upshot is although quite pricey, playing COD4 and Gears of War late at night I've nearly S**t my pants on a couple of occassions. Highly Recommended