I have a set of turtle beach PX5 and looking at the instructions on the turtle website they look pretty similar,i know mine cost around £160 about 8 months ago and i also have them connected with a optical cable into my xbox and had to change a few settings and muck about with both the turtle beach unit and the xbox settings for sound.
I guess you have looked at the xbox menu settings and have synced the turtle beach headset to your 360,dont know what to suggest but i will look exactly how mine is connected both from the turtle beach unit [what light are on ect] and the xbox sound config if you like.
Let me know and i will post on here or try and help you in some way.
,only thing i hate about it is the fact that i have to keep taking out the optical cable from one console to the other and the fact that the headset dont charge the batteries and it costs a small fortune when gaming a lot.
Sometimes turning the unit of and taking out the optical cable and restarting helps these sort of issues,as this has happened to me in the past.
Apart from that the sounds brilliant and the headset nice and cozy .
Edited by time2die (Sun 17-Jun-12 00:55:47)