This extension mutes previous audible tabs when a new tab starts making sound. Toggle mute current tab: Cmd+Shift+8
This extension lets you control mute status of multiple tabs. Often, one listens to music in a tab, but occasionally one would open another tab with a video or something - this extension automatically mutes the previous tab. It works like a stack, last audible tab gets to make sound, all previous tabs are muted. Once the new tab goes silent, the previous tabs are unmuted (one at a time, only one tab will be audible at a time).
Besides that, you can mute all tabs with Cmd+Shift+0.
unmute all tabs with Cmd+Shift+9 (although, if you have multiple audible tabs, only one will remain unmuted, rest will be muted by extension.)
Toggle mute status of a single tab with Cmd+Shift+8.
Any tabs you mute with these shortcuts will not be unmuted by extention, you have to unmute with the one of the shortcuts.