I was looking in to it, because some websites are full of advertisements, and sadly, a lot of them have sound. It also helps if you like listening to music and want to mute everything BUT the music. It’s really simple, and if you didn’t know how yet, you’ll probably feel dumb after I tell you.
Right click the speaker icon
Click “Open Volume Mixer”
Find the application (IE, Firefox, Chrome) you want to mute
Turn the volume of the app down with the slider
I posted this to help anyone who didn’t know about this like I didn’t until 5 minutes ago.