hmm...i had a similar problem when i hooked up my ipod to to my clarion fold out..i actially had the ipod tucked behind the HU...so not accessible without pulling the hu or ac controls out...but anyways when i had that set up i was getting this whining sound almost like a ghetto turbo spooling up sound coming from my speakers...well i found out that it was the alternator interference and that was caused by the ipod being to close to the other wires and was somehow conducting there signal...could your zune or ipod be to close to your wires?...try switching sides of your wires from behind the hu?...wrap up in electrical tape?...i dont know just throwing up ideas...mine went away when i relocated my ipod to the centerconsole...and i ran my ipod cable on the opposite side of where my other wires had come out of..hope i helped but prob didnt...DG