From what I can remember mic,s only work with people who are your friends or rivals, who have also got to have mics plugged in.
Normally you can speak to people whilst in the Lobbies.
It is also possible to speak to fellow mic users whilst in game, but sometimes it can be very off putting to hear others when trying to play the game. --- NNID - AndyInTheUK Mainly playing Zombi U. Currently Number 4 on the Standard mode Leaderboard for Zombi U. http://i.imgur.com/YD02k.jpg