subwoofer problem

ok, this just happened like 2min ago.

the subwoofer vibrates & its noisy, however, it goes away when playing music, and when a browser is loading a webpage, but as soon as the computer is in an idle state it makes noise, if i put the volume low, it goes away, i never had this problem before

wtf is wrong, and how i do i fix it?

these speakers (Creative GigaWorks ProGamer G500 5.1) are about 1 week old...