My IO shield is routing noise through my computer speakers.

For some reason I only receive interference through my speakers when my IO shield is installed. I've tried aligning the tabs to contact the motherboard connections, but that generates a lot of noise through the speakers. I tested it outside of the case and installed in the case (without the IO shield) and there was zero noise. Isn't my IO shield supposed to prevent this? So, I have the shield installed, and of course there is still a miniscule, but annoying amount of noise through the speakers. It's definitely the IO shield! I'm stumped, not sure what to do. I could take it to a local repair shop and let them be responsible for it, but I would really like to solve this myself. Note: the sound cannot be reproduced with the use of headphones (Strange). Any help would be appreciated.

Drivers are all current, mic and line in are muted.
-Antec 1200 V3
-Antec 850Watt CP 850
-MSI p67a-g45 (B3) (Using onboard audio)
-EVGA 560 TI Superclocked

Try fitting ferrite choke coils to your audio cable, at both ends, or upgrading the cable used to something. Consider perhaps making a custom I/O backplane from plastic sheeting, such as perspex, if you're unhappy with the manufacturers own design - but remember the backplane purposefully grounds the metal port enclosures to your PC case too, which helps protect the mainboard against ESD hazards.

The Ferrite Choke Coil sounds like it might work, but where exactly would I get those? How would they attach to the cable?

Bit hard to say as you've yet to fill out your location, or your system specs'...

Try Radiospares (RS Components) or Maplins, Tandy, or Radioshack...