Annoying unwanted background audio in safari
I am using MacBook Air with OS Sierra 10.12.3 and Safari 10.12.3. Suddenly, whenever I use safari, I get an annoying background audio which I cannot eliminate, although I can mute the speaker. if I then try to play an audio selection from a chosen website, I get a cacophonous amalgam of the annoying background and my own selection. Sounds like I've acquired some sort of malware. Any ideas for a fix?