Bad Speaker static

[Donnation25]

I've got the altec lansing FX6021 speaker system hooked to my imac g5. Whenever they are on, the static that comes of them is really bad. I used to have the logitech Z-2300 speakers set up in the exact same position and there was no static. They are set up about 2 feet apart from the imac with the subwoofer on the floor. I can't hardly stand to turn them on it is so bad. Can anybody give me some advice on what the problem might be??? Thanks