The provider has placed space for ads on the bottom of the screen, and one of those ads is one from HP that emits loud rock music. But not everyone is notices it: presumable a lot of the patrons use anti-ad software. Also, you don't notice it if you have your boxes turned off .

I have stopped playing music on my PC when visiting the Org, because the HP-ad makes so much noice that I can hardly hear the CD playing.