How to disable the find sound in firefox
When you hit ctrl-f and search in Firefox, it will follow along with your typing to the first / most significant match on the page. But once your typing misses a word, Firefox beeps and blips at you as feedback. For example, the Google page has the word “Advertising” on the page. If you hit ctrl-f and type “Advertizzz” then you will be greeted with three blips. That kind of feedback is annoying in my opinion. The red color in the find box is enough feedback for me, so I wanted to silence the beep.

So here’s how you disable it. Go to the url about:config and set a key called “accessibility.typeaheadfind.enablesound” equal to “false”. Restart Firefox. Should be silent now.