If you are experiencing audio issues, you can adjust the record volume of your input sound device by sliding the "Broadcast Volume" bar in the broadcast window. RED means your are overloading the recording sound. You can also adjust your record volume in your computer sound settings
To do this through flash, right-click on the broadcast window (ctrl and click for Macs) and select SETTINGS.

Click on the microphone icon.

Lower the record volume bar until you do not see RED on the side bar.