I really have problems to understand what the cause is for this: Lately one of my audio interfaces failed, so I had to switch to an interface only supporting non-symmetrical connections to the speakers (2 wires instead 3). Now at this place here, I again can hear now the cpu and harddrive accesses in the speakers as kind of digital “noise”. And the more cpu load, the louder it gets 
. Though on the other place I do music, using the same audio interface and computer, I do not get those noises. The only difference is the speakers and the place/electrical wires. I also tried to switch the power sockets, it seems to be a bit quieter then, but no real change.
So is it caused by poor shielding in the speakers? The current speakers are Presonus Eris E8. I think Presonus hardware usually is pretty nicely shielded, but I don’t know. I also checked the grounding of the power sockets with a multimeter, seems to be alright.