If you notice a low frequency hum noise (Buzz) coming through your speakers 
it is most likely a "Ground Loop". To correct the problem:
  
  If there is any three prong AC Cable in the chain, lift the ground pin on 
  the AC cord with a 2 prong adapter. If this does not help, it is probably
  another cable that has failed. Replace it.

  Lifting the ground pin on the AC cable is suggested only as a way to find
  the source of the hum problem. If the hum goes away when the AC ground is
  lifted, it indicates that you have a ground loop between the Turtle Beach 
  product and the video / audio / TV equipment into which it is plugged in.
  You should find the source of that ground loop, correct it, and then 
  reconnect the ground on the power cord. We do not endorse lifting the ground
  permanently, as it is contrary to the UL certification on the device.

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Here are two other ways to break ground loops: 

  Radio Shack ground loop isolator (product #27-054) 

http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=
CTLG%5F002%5F001%5F019%5F008&product%5Fid=27%2D054

Read more about ground loops at: 
http://www.elect-spec.com/faqgrdl.htm 

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* If your system has hum in your video and audio, Jensen transformers has a 
  very nice isolation transformer for decoupling the cable TV from all your
  equipment. They have other transformer and isolation products. Jensen also
  has some very good tutorials on hum and their causes. 

  http://www.jensentransformers.com/iso_vid.html 
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