Just like oczdude8 said, change your power source to another outlet (maybe the bottom outlet). It seems to me that there is a grounding issue with your speakers. That "tzzzz" sound it seems more than likely a electrical signal that is not going where it is supposed to. If your power source is grounded then the issue lies with the speakers them-self. Make sure there are no loose wires or connections on the device. If everything does checkout then the issue should lie with the manufacturer. Take up the issue with them if you are under warranty.