How to mute all sites by default in Firefox
Mute sites by default is a new add-on for the Firefox web browser that changes the default state of all sites in Firefox to mute.
Firefox, like any other modern browser, plays audio by default if a site chooses to play it. Some sites play videos with muted audio, or audio only when you interact with elements on the site, but others may play audio when the site loads advertisement, videos, or music.
Note that recent versions of Firefox (and other browsers) try to suppress autplaying sound on sites. Firefox users find the option to enable or disable the feature under Permissions on the about:preferences#privacy page.
We talked about options to mute sites permanently in Firefox before. This is useful if you visit sites regularly that play audio that you don't require, or that you want muted by default.
Mute all sites by default in Firefox
The new Firefox extension Mute sites by default blocks audio on all sites by default in the browser. Any site you visit is blocked from playing audio, or more precisely, the audio that sites play is not audible as it is muted in Firefox after you install the browser add-on
You may unmute any site by clicking on the speaker icon in Firefox's tab bar, right-clicking on the tab and selecting the mute tab / unmute tab option, or by using the shortcut Ctrl-M.
The extension comes with a whitelist that you may add domains to that are allowed to play audio by default in Firefox. If you visit Dailymotion regularly, or watch videos on Facebook, you may want to consider adding those domains to the whitelist to make things easier.
Note that muting or unmuting a site will update the whitelist accordingly. While that is convenient at times, it means as well that you need to remove the whitelist entry or mute a site again if you only want to allow sound to be played temporarily on it.
Mute sites by default is a WebExtension. This means that it is compatible with Firefox 57 and newer versions of the browser.
Google tests an option in Chrome currently to silence sites permanently using built-in browser controls.
Firefox has seen its fair share of extension releases to mute audio in the past. Muter for instance adds a toggle to the browser to mute/unmute all sound in the browser. The extension is not a WebExtension, and as such unfortunately not compatible with Firefox 57 or newer.
Another interesting extension for Firefox is Smart Tab Mute which restricts audio playback to a single tab. This add-on is a WebExtension.Advertisement