Possible to pause audio in browser using keyboard?
I can't find a way to do it in Chrome, but in Safari it's easy.

Method as follows, in case it would provide a suitable alternative...

You can click on the speaker icon to the right of the address bar to mute either the current tab or all tabs - the Mute wording appears as you hover your cursor.
A single click will mute even if Safari is not currently frontmost, so long as you can see the icon. [It will then bring it to the front, though.]



You can also set a key command to Mute This Tab or Mute All Tabs in System Prefs > Keyboard > Shortcuts >App Shortcuts - though this requires Safari to be frontmost to work.