Only thing that could make this better is if it could mute/unmute sites based on if a certain audio device (such as headphones) are connected or not. Granted, I'm on Windows, so I don't know if that'd work on other OSes, but it'd be nice to have.

so good

Thank you so much - muting domains instead of tabs was the number one Chrome feature I missed. This extension does exactly what I wanted and improves my browsing experience a lot.

I just added this to userChrome.css to remove the ugly "MUTED" label by Firefox:
.tab-secondary-label[muted] {
display: none !important;
}

When I press ctrl+m it mutes/unmutes multiple tabs from the same domain, even though they have different subfolder address. I expected only the current tab to be affected and keep every other tab muted. Would be nice to have different keybinds to whitelist domain and mute/unmute current tab.

Thank you. Works well.

However, with most/all tabs muted, the "muted" icon next to each tab is taking space, it's visually noisy and it hides/replaces the site icon.

Remedy: Hide "muted" icon unless a tab is currently playing sound.

How? create "userChrome.css" file with the following content:
@namespace url(http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul);
.tab-icon-overlay:not([soundplaying]) {
display: none;
}
.tab-icon-image:not([soundplaying]) {
opacity: 1 !important;
}

Save that file in chrome folder right under your Firefox profile folder. To locate that, open Firefox special URL about:support and see "Profile Directory". See also https://www.reddit.com/r/FirefoxCSS.

As someone who forgets he left his speakers on, this addon has been a lifesaver.

Doesn't work anymore. Not sure why, not going to troubleshoot because an alternative is already working without issue, thanks for the last few years though!

Couldn't unmute all tabs when decided to remove the addon. Spending precious time unmuting by hand. Pretty pissed.

why EXACTLY this exists ?!?
if it add all by itself the very one site I REALLY NEED TO MUTE to exceptions ?!??!?!?!?!?

This is great for those annoying mini videos that play on sites that you visit to download a freeware program. They pop up telling you how to install the same kind of programs over and over again its annoying. So this really helps with those videos.

An essential add-on for Firefox. Congratulations on your great work.

Simple and good! Needed this very much.

Been using it for some months now and works as expected. 👍 Had to get used to it at first though, there were moments I thought YT has a new feature to mute embedded videos in other sites because I got no sound xD 🤦