In HTML, when you go to a new page, background music can't continue. This is a good thing - otherwise, if one website you visited were playing music, it could continue, even when you go to a completely different site.
In a Saturn album, the top level is one web page. Each folder is a separate web page. So, the music can't be continuous when you open a folder. When you go to a folder, the music will start over from the beginning.