Hi, sorry not able to hear. *https://support.mozilla.org/en-US/kb/fix-common-audio-and-video-issues *https://support.mozilla.org/en-US/kb/fix-video-audio-problems-firefox-windows *https://support.mozilla.org/en-US/kb/html5-audio-and-video-firefox Can try in Safe Mode *https://support.mozilla.org/kb/Safe+Mode *https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes In Firefox Safe mode these changes are effective: *all extensions are disabled (about:addons) *default theme is used (no persona) *userChrome.css and userContent.css are ignored (chrome folder) *default toolbar layout is used (file: localstore-safe.rdf) *Javascript JIT compilers are disabled (prefs: javascript.options.*jit) *hardware acceleration is disabled (Options > Advanced > General) *plugins are not affected *preferences are not affected TEST REFRESH INSTRUCTIONS Please Refresh but do this 1st: Delete your Cookies and Cache and TEST. *https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer *https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles then *https://support.mozilla.org/en-US/kb/refresh-firefox-reset-add-ons-and-settings TEST....... If no issues then Extensions which need to be added back in 1 at a time and tested ..... Or it is your Profile : Make a new one and test ...: *https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles If is your Profile : *https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile *http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox Note: Any customization will revert back to default, you will also need to reinstall Extensions. Please let us know if this solved your issue or if need further assistance.

I tried all of this BEFORE I asked here. I've had this problem for more than 2 years.

Do you have PulseAudio installed? https://bugzilla.mozilla.org/show_bug.cgi?id=1247056

I have tried both with and without pulseaudio. When I have pulseaudio running I have run pavucontrol, turned the volume all the way up, made sure speakers were unmuted.

You can check this article: [[No sound in Firefox 59 on Linux in some configurations]]

pulseaudio is running. Removing '--disallow-module-loading ' solves my problem. This security measure is in Slackware's rc.pulseaudio. I'll tell them about it.

Hmmmm... I was running as root when this fix worked; when I run as myself it doesn't. (Yes I tried it as root before) so I have a permissions problem too; would anyone know what? I've looked at lsof's output but that hasn't helped.