Can't stop high pitched speaker whine

[Howard60]

I've speakers in the ceiling powered by an tuner/amp. Friday I had hooked up my computer to feed tunes through the amp to the speaker. At end of evening, I turned off everything-- high pitched whine continues 24/7! Suggestions?

 

[mauller07]

so is the amp and the computer connected to them not powered and the speakers still whine?

are they near any power cables or lights in the ceiling?

if they have power cables running over them at all, insulate the speaker cables in tin foil and earth it if possible, you could also cover the back of the speakers in chicken wire to reduce EMI, just make a done around the top backs of the speakers.