More than likely it's an auto-play ad (although there shouldn't be any). If you can locate the ad, we can block it. If you are using firefox, any tab that is playing audio will have the speaker icon next to the "x" on the right of the tab. That will allow you to tell if it's the RPF that is generating the music and you can click on the icon to mute it. I know that chrome shows the icon if audio is playing but I don't think that you can mute it just by clicking on it (there may be a setting that allows that).