When a tab tries to play sound there is a Mute Icon on that tab which is on the tab which could be on the left.
I just got an HP 15-db0061cl laptop about a week ago, and about half the time when I am browsing the web using firefox, a white silhouette of what looks like a volume/speaker icon shows up on the left side of the screen. It only shows up for a few seconds each time it comes up. Coincidentally, this always happens when reading stories on MSN. This laptop does have AdBlock installed, and MSN does have a message saying that "they are having a hard time interacting with the adblock software." Would that have something to do with it? Should I consult MSN regarding this? Any help is appreciated, thank you.