An anonymous reader shares a report: If you're a Linux user who upgraded to Firefox 52 only to find that the browser no longer plays sound, you're not alone. Firefox 52 saw release last week and it makes PulseAudio a hard dependency -- meaning ALSA only desktops are no longer supported. Ubuntu uses PulseAudio by default (as most modern Linux distributions do) so the switch won't affect most -- but some Linux users and distros do prefer, for various reasons, to use ALSA, which is part of the Linux kernel. Lubuntu 16.04 LTS is one of the distros that use ALSA by default. Lubuntu users who upgraded to Firefox 52 through the regular update channel were, without warning, left with a web browser that plays no sound. Lubuntu 16.10 users are not affected as the distro switched to PulseAudio.