So I noticed when I turn on my Focal Shape 65 studio speakers, sometimes I'd hear the right speaker hiss more than the left. At first, I thought really bad about it -- I escaped from KRK Rokit5 just to solve this problem, only to get it again? It's impossible!
Then I read somewhere that when my balanced audio cable is on top of a power cable, it'll create a hissing noise. So I did an experiment by literally putting part of the audio cable on top of one of the power cables. The hiss came in! When I lift the audio cable, even slightly from the power cable, the volume of the hiss decreased. And when I asked my dad to move all XLR cables away from nearby power cables, the hissing stopped.
OK, so what I read was in fact true. But, why? Why was I first of all hearing this hiss? And why does a simple separation of the cables become the solution for the hiss problem?
Many thanks for answering this question!