This works very well outside of a browser, too. For example various beeps from Window Manager or terminal emulator or particular programs can be very irritating and disabling them all means going through endless pile of different "settings" dialogs.

It breaks down, however, when you want to listen to some music while working. In the end I have my audio muted most of the time, but over time I had to go through all those settings anyway.

this seems like a much easier (and more foolproof) solution....