Other sites mention as well as the achievements list mention the use of a mic. (For a second person or yourself i guess to sing along while the other person rocks out on their guitar)
Anyone know how to use this? I tried using the wireless mic headsets on the xbox controller. Tried on 1st player and 2nd player controllers with loaded profiles for each player. Then tried singing during play with both controllers. No singing heard through the game. I also tried the multiplayer screen option but that wont let you get anywhere without another guitar/cable plugged in.
I also looked under options /stup and couldnt find anything.
My only other thought was it has to be a USB microphone instead of headset? I tried writing ubisoft but they responded with "using a mic will stop a player from collecting points and errors" which really didnt answer this question :)