Offizieller Kommentar
That, my friend, is called a ground loop. This can likely be eliminated by simply using an ungrounded power source for the speaker. For example, you can grab 3 cheater plugs at your local hardware store:
And put one on each speaker and on the power strip your mixer is plugged into. Or simply remove the grounding prong (the round one) from those power cables and power strip.
Aktionen für Kommentare