Youtube is the most popular video sharing website where anyone can upload their videos to be admired and commented on by the people from all over the world. You can subscribe to your favorite Youtubers who put a lot of hard work in their videos for your pleasure. And every time you check Youtube in your web browser it shows all the latest videos uploaded by those Youtubers and sometimes you get so excited that you click on more than one of them to be opened in new tabs. This is when the videos start playing in more than one tabs and you hear the sounds coming from from all of them.
A similar situation is encountered when one of the news websites start playing video clips as soon as you open them. To prevent Firefox from playing the sound from more than one tabs simultaneously, you can use the “Smart Tab Mute” extension. What this extension does is that it mutes all the previously open tabs automatically when you open a new tab in which sound is playing. This way you do not hear the noise caused by all the sound being played from a number of tabs but you hear only the sound from the newest tab that you have opened.
But there are times when you do want to hear the sound coming from the background tabs, for example, when you are using an online messenger web app, listening to online radio or perhaps listening to podcasts. The Smart Tab Mute extension gives you option to add the domain names for which the background tabs are not muted. In the settings, you can also choose to unmute the last tab which unmutes the previously muted tab (muted by this extension).
Conclusion: Auto-muting all the tabs except the one you have opened most recently can be easily achieved through an extension called Smart Tab Mute in Mozilla Firefox. You can also specify some exceptions in the settings so that for them no muting is done.
You can download the Smart Tab Mute extension for Firefox from https://addons.mozilla.org/en-US/firefox/addon/smart-tab-mute/.