How do I get rid of the buzzing noise in my speakers?

5.1 Speakers. Buzzing Noise.?

• Hi Currently i have the logitech 5.1 surround sound speakers connected to my PC via the 3 RCA inputs. It works great and i get 5.1 sound. I then got a optical cable from my ps3 to a optical to coaxial converter and put the coaxial cable into my PC's input (this is because i don't have a optical input on my PC) I then set my PC to play the audio from the optical to my speakers. It worked okay on stereo and i would get sound but when i changed to 5.1 or 5.1 dts all i get is a loud buzzing noise. I know its not my speakers as my computer plays 5.1 through it properly ( i tested it out in left 4 dead 2). Also on the realtek audio manager on digital input it says AC3 (which is 5.1 surround sound) This is really frustrating as i don't have enough money for a home cinema (which is why i tried to connect through the computers) and my speakers also only have RCA input. The problem seems to be from the computer to speakers as i think the sound isn't being decoded and sent through each RCA cable separately. Is there anyway to fix this as i really want to get this working. Thanks in advanced!

• Answer:

  its probably just EMI <electro magnetic interference> either through the subwoofer being too close to the something electrical. try moving the speakers around and see if it goes away.