I've had firefox for a long time on multiple computers, and on the one I'm using now for 8 years. Only within the past two months has this issue popped up. That being: I ''cannot'' get any audio from youtube no matter what. There is no speaker on the tab to show it, and I don't mute my tabs ever so it's not that. Even muting and unmuting it does nothing. The video ''always'' buffers for 5 seconds upon loading the player before autoplaying with no sound. Every video does this, EXCEPT for if it's flash based which I tested via [https://www.dhs.state.il.us/accessibility/tests/flash/video.html this link]. Flash audio players have no problems either. The speaker icon DOES show up for these ones, but nothing else. And there's another problem... sometimes, it fixes itself! Out of nowhere, while I'm doing something else on my comp or on my phone (just away from the browser in general) when I let it loop through a playlist, the sound just happens. It startles me every time, because there seems to be no rhyme or reason. I've done the common checks you do for your computer audio and it's none of that. Browser only. Restarted comp and refreshed firefox; nothing. Completely wiped firefox from system and reinstalled (which gave me a whole new host of issues for another topic); still nothing. For 2 months it's been agonizingly painful trying to get answers so I can stop focusing on it.