In April I bought these speakers - http://www.ebuyer.com/94472-logitech-x210-2-1-speakers-970191-0120 - The speakers connect to the sub-woofer and the sub-woofer is connected to the mains, the audio card and a controller dongle.
When I first bought them they crackled a little but I just put up with it, it had happened with the same computer on my old speakers. Having moved house this week I took a little time to try and figure out what the cause is.
I have noticed that the crackling only occurs when my PC is on. It is less frequent when going through POST but picks up when Windows starts loading. It continues whilst the computer is idle but can become louder and more frequent when I am actually using the computer though I cannot figure out a pattern for this.
The crackling occurs whether the sub-woofer is connected to the computer or not. I guess this rules out drivers or volume.
I have tried moving the speakers away from the computer and the crackling doesn't stop or become quieter.
My housemate has suggested that it could be a component inside my PC interfering with the speakers or even perhaps some other device being amplified by the PC.
Is there a way to work out what is causing the crackling or protect the speakers from interference caused by something else?
[I am currently at work at the moment and won't be able to try suggestions til later tonight. I am already planning on trying to connect the speakers directly to the computer instead of the sub-woofer and try to plug it in further away from the PC.]
------ Edit -----
I've moved a few things around and it seems the interference dies out when the 3.5 connector is moved away from the computer and increases substantially when moved close to the audio card. I can't detect a difference when moving around close to the PC so it could be anything in there that's causing it.