Problem: Inexplicably and sporadically, ALL flash audio is mute in FF when using a wireless G930 headset connected to USB dongle (physically or wireless), but everything plays fine in Chrome and Explorer. I'm here to tell you what worked for the sake of others, and to make the FF team aware of a problem worth their attention. Statement: Everything is up to date. FF, extensions, Flash, Java, Windows. I uninstalled flash on FF and my machine and reinstalled on both. My headset audio device is correctly activated in WIndows Audio Devices - all other devices are deactivated. My current solution: I learned from a prior FF issue involving YouTube videos that YT has something called DASH playback, requiring you to plug in an audio cable to your machine, or the video won't play (WTF right?). An extension called "YouTube Center" fixes this by allowing you to turn off DASH playback. After plugging in a set of earphones into my computer's audio jack, I activated the audio device on the machine, and got audio through the earphones and headset. I then disconnected the earphones, and disabled the audio jack. Audio now works fine on the headset, and I've rebooted the machine, turned the audio jack back on, rebooted firefox multiple times to make sure. Currently, things are fine, but I'm reluctant to plug anything back into the jack. For some strange reason, FF seems to have trouble recognizing my G930 headset as a valid audio device, or that's my guess. The fact that everything is peachy in other browsers should narrow down the culprit. Hopefully this helps someone else, and we can find out what the core bug is to make things right. Ask any questions if you have them and I'll try to get back.