I'm trying to use my Macbook pro as a bridge between my Xbox 360 and my speakers. I have the sound on the Xbox 360 outputing to the line-in port on the MBP, and when I go into the Sound settings I can see that the computer is picking up the input. Now I want to set the mac to output the sound coming in the line-in port all the time. How do I do this? Is there a way in OSX? Can I get an external app?