Running Firefox 83 (claims it's up to date) on Windows 10 Pro N. Recently Firefox has decided to play the audio from the likes of Facebook videos and YouTube through the speakers, despite: # the headphones being the default device # restarting the computer # Chrome and VLC media player both sending audio to the USB headphones. I disabled the speakers, which did result in FF sending the audio through the USB headphones. But . . . when I re-enabled the speakers Firefox reverted to them. Mid-play of a video! This even though the default audio device was still the USB headphones. I searched for guidance, but the mentions I have found related to posts going back several years (FF 36 anyone). That other applications correctly recognise the appropriate audio device suggests strongly that it's a Firefox issue, rather than an OS issue. I really would prefer to not have to manually disable the speakers. Previously everything would simply switch from headphones to speakers when I unplugged the headphones, and back again when I plugged the headphones back in. This is how it ''should'' be.