Static from speaker?

Hi i have the JVC THB-5000 Home Theatre System and noticed that six months down the road, the rear surround sound speakers makes static and crackling noises. I know that i havent done anything to it to damage it, it has nothing to do with the connections, placement positive negative inserts of the wires, etc.. Is there a way of fixing the speaker? Any help, would be greatly appreciated!!

 

have you tried changing speakers just to find out if it's the actual speakers or receiver??