Mute Sites by Default is a Firefox addon that significantly improves browsing by preventing unwanted audio from websites. This free tool automatically mutes all sites unless they are whitelisted by the user, allowing for a more focused and quieter online experience. Users can easily manage their whitelist to permit sound from selected sites while keeping others muted, effectively reducing distractions during web navigation.

The addon features multiple methods for controlling audio preferences, including clicking a speaker icon on tabs, right-clicking for mute options, or utilizing keyboard shortcuts. It also supports the use of wildcard characters in the whitelist, making it simple to manage audio settings for several subdomains. This flexibility enhances usability for users who frequently visit specific sites, ensuring a tailored browsing experience.