I'm not sure if other browsers or programs have this issue, but I've noticed it while using Firefox, on YouTube or Pandora. When a new video/track begins, the output audio of the browser (not the main volume) becomes lower. My guess is something trying to optimize sound quality, but when I'm making a bunch of noise, I need volume over quality. Pictured is my audio window showing the new Firefox audio being lower than it was before.

screenshot of Playback tab in Volume Control

  • you can find lots of similar bug reports like this support.mozilla.org/en-US/questions/1201925 it's been for a couple of years now.
    – JoKeR
    Nov 9, 2019 at 0:03
  • also similar askubuntu.com/questions/967061/…
    – JoKeR
    Nov 9, 2019 at 0:11
  • 1
    I tried the delete /mozilla folder suggestion from the other topic. I had to reset all my passwords and bookmarks, but the problem persists. In fact it seems worse. What used to be a drop to 80% is now dropping to around 60%. The support link seems to be a solution for windows. I could not find an ubuntu solution there. @JoKer Nov 10, 2019 at 1:34
  • I meant to say that it is a bug not only for Ubuntu and it's been happening for years so you'd better file it as a bug report.
    – JoKeR
    Nov 10, 2019 at 21:38

1 Answer 1


In case someone comes across this question (as did I), there is an answer here: Inconsistent Sound Volume Ubuntu 20.04

Basically, you need to change flat-volumes = no to flat-volumes = yes. The values "true", "1" and "on" are equivalent to "yes", according to the manpage (https://manpages.ubuntu.com/manpages/focal/man5/pulse-daemon.conf.5.html):

For the settings that take a boolean argument the values true, yes, on and 1 are equivalent, resp. false, no, off, 0.

Don't forged to uncomment the respective line by removing the ";" or "#":

The configuration file is a simple collection of variable declarations. If the configuration file parser encounters either ; or # it ignores the rest of the line until its end.

The configuration file is: /etc/pulse/daemon.conf

Other possible locations are: ~/.config/pulse/daemon.conf, ~/.config/pulse/daemon.conf.d/*.conf and /etc/pulse/daemon.conf.d/*.conf:

The PulseAudio sound server reads configuration directives from a configuration file on startup. If the per-user file ~/.config/pulse/daemon.conf exists, it is used, otherwise the system configuration file /etc/pulse/daemon.conf is used. In addition to those main files, configuration directives can also be put in files under directories ~/.config/pulse/daemon.conf.d/ and /etc/pulse/daemon.conf.d/.

According to the aforementioned post, rebooting is necessary for the change to take effect.

About the configuration option:

flat-volumes= Enable 'flat' volumes, i.e. where possible let the sink volume equal the maximum of the volumes of the inputs connected to it. Takes a boolean argument, defaults to no.

EDIT: I tested the solution myself and it worked (Ubuntu 20.04).

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