How to broadcast audio -  To broadcast audio, a microphone is necessary. I use and recommend speaker / mic combination headsets for chatting, so the rest of the household isn't disturbed by the chatter.  When in a room, to  broadcast audio to other users, simply mouse click on the green "talk" button in the lower left hand corner.  If you need to talk or hold down mic for an extended period of time, you can right mouse click on the talk button to lock it down.  Remember to use the right mouse button " lock" feature if you will be broadcasting for more than just a couple of seconds - I have noticed that if you try to hold down with the left mouse button for extended periods of it that you can get 'stuck' on mic.  If you do happen to get 'stuck' on mic, simply close out the program and return to fix it promptly.