As the title said, there's static noise coming from both my new Eris 4.5 monitors, even when only the power cable is connected. It's noticable from several meters away and is really annoying. When I plug my headphones into the phone jack on the front the noise stops completely though, and there's no noise from the headphones. Again, this has nothing to do with the actual audio cables.
I've already tried different power outlets and also turning everything in my room off except the monitors, but with the same result. Is this a cause of bad grounding or dirty power or a problem with the speakers that I got?