Logitech X-530 5.1, interference

[Banzai_Joe]

Hi all,
back from my *ahem* short break

I have the above named speaker sets with two core2duo based rigs that are almost identical, based on the Gigabyte GAP35c DS3R, one using onboard 5.1 sound, the other using an x-fi pcie 5.1 sound card.
Both seem to suffer from interference, i.e. at any given random time you can hear some kind of audio coming the centre speaker. Its clear enough to make out, and it sounds like some kind of radio talk show or similar.
One of kids justifies his excessively loud volume by saying that its the only way to drown out the interference, which leads me to think that its nearly always there.
There is a 3rd almost identical rig that only has a 2.1 speaker set, which doesn't suffer interference. But this could be either cos its a different make of speaker or that it doesn't have a centre speaker.

Any ideas anybody, please?

 

[Banzai_Joe]

Thanks Chris, i posted this same thread on another forum and a user has replied with the same as you, same speakers.
He said that the centre speaker needs checking for correct earthing OR replace the cable with a shielded one.
A guy i work with has just corroborated this as he installs video/audio surveilance and know about this stuff.

 

[Banzai_Joe]

Checked the centre speaker, but its a sealed unit so changing the cable would be more trouble than its seemingly worth.
Went back to PC World and told them my problems, and they shrugged and offered a refund. Great! Can't be bothered to change both sets out as the cables are trailed behind furniture etc and i'd have to pay extra to get a different/better set.

Looks like i'm stuck, unless someone can offer a better solution.