How was your golf game this morning?
Chances are that it's not a virus.
Make sure you have no other windows or applications running and hidden. It could be from an ad in your broswer. You might have more than one window open (but one is hidden).
Sometimes it's not directly the Youtube proggie itself...but it's from an ad that pushed it's voice in either from an accidental click from just mousing over with your cursor or it's an ad that starts from the video clip itself. You'll usually see an ad that will end in 5 sec or 30 secs. Make sure you click them off.
However if the voice keeps on running while the music is playing, it's due to a second window open or an ad on the side of your screen that needs to be halted.