I left 5 stars because it uses to work really well. But not longer works at all since WaterFox 5.0. It no longer mute new tabs.

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.

Hay addons que tienen ochentamil opciones y van fatal. Esta, en cambio, para lo que hace que es sencillamente poner en silencio automáticamente las pestañas nuevas que abres, va genial. Es una de las pocas extensiones de las que no he buscadp alternativas porque como digo, genial.

Completely purrrfect for private porn watching :)

"Must have" ;)

Very good work

Exactly what i was looking for, very nice!

Could you add a feature so that one would be able to add exception like:

youtube.com/*
randomdomain.eu

YAY!! The CNET-Download website has been driving me CRAZY For Years with their Idiotic Video that (Aggravatingly!!) Auto-Plays Every Time you visit their site. Now, that idiot site is blessedly SILENT! Thank You to the Author of this Great Extension!

Does exactly what I wanted from the extension. A whitelist feature would be very welcome but a luxury I can live without.

Works with the new Firefox Quantum. Easy to use.