Here is a link to some fixes for common audio and visual issues :  Fix common audio and visual issues {link}

Hi John, I am sorry to hear you're having audio issues with Firefox. I would try restarting Firefox in Safe mode if you haven't already. # Click the '''menu''' on the top right of the browser # Click '''Help''' # Click '''Restart with add-ons Disabled...''' Here is a ''link ''to some fixes for common audio and visual issues : [https://support.mozilla.org/en-US/kb/fix-common-audio-and-video-issues Fix common audio and visual issues] {link} Did you disable any settings in about:config? Here are some related questions/solutions on the Support Forum: [https://support.mozilla.org/en-US/questions/1236919 sound not working ONLY on firefox] {link} [https://support.mozilla.org/en-US/questions/1165581 Why no sound when using Firefox; sound when using other browsers?] {link} Let me know if this helps.