Don't bother, because if you're using any kind of cable, it should be immune to any kind of wireless interference.
Now, just to be sure we're talking about the same thing, the cables you're using look something like the example pictures here, right?
http://en.wikipedia.org/wiki/TOSLINK
Model: Samsung Soundbar HW-C451
Connection type : optical
I purchased the Samsung Soundbar HW-C451 a few days ago, and have loved it so far. I have 3 devices I swap between the 2 optical inputs. (Mac Mini, PS3, Xbox 360). The PS3 and Mac work without problems. However, The second I turn on the Xbox 360, I can hear a humming noise coming from the soundbar (both speakers). This is not present with any other device.
I have tried 2 different Xboxs (Elite, regular), also swapped the optical cable for a known good cable, also swapped the VGA video cable on the Xbox. (we have 3 in the household). I have also unplugged all other devices in the room, including the wireless sub, to minimize interference. The problem persists.
The only other thing I can think of is the wireless router in the house. I have disconnected the wireless on the xbox, but have not yet changed the frequency settings on the router.
Any thoughts? Help would be greatly appreciated.

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