Firefox lets you identify noisy tabs and mute them in a single click. Silence tabs quickly without affecting your other tabs or windows.

Mute or unmute tabs

When sound starts playing while you're browing, Firefox lets you know where it's coming from by displaying a speaker button on the noisy tab. Click the speaker to turn the sound off or on for that tab alone.

Tip: You can also mute multiple tabs by selecting them (Command-clickCtrl-click), then Control-clickright-click one of these tabs and select Mute Tabs.