Soundman by MrOtherGuy

Soundman adds an entry to context menu for tab which starts to play audio.
Menu entry shows the tab title as well as current state of the tab. The menu entry can be used to perform different actions on that tab selected by configurable modifier key (Ctrl, Shift or no modifier).

The actions are:

• Mute/Unmute tab
• Switch to tab - selecting the same context menu again switches back to originating tab
• Play/Pause media - whether this works depends on website

Optionally, Soundman can mute other tabs automatically when active tab becomes audible. Likewise, a previously automuted tab is unmuted when applicable.

You can configure hotkeys to mute and pause playback in background tabs. If a hotkey doesn't work, it's probably in use by Firefox itself or other extension. Try another one.

Additionally, you can pin sites to Soundman by using the entry on tab context menu. This way the tab isn't removed from Soundman unless you manually remove it or the tab is closed - No state persists between Firefox restarts however.

Soundman requires wide permissions for all tabs and data. Unfortunately this is necessary because it needs access to tab title and because play/pause functionality needs to send a short script to the content.