Okay, I've found this in my KRK user guide...
"Check the connections between
the signal source and the monitor. The monitors Neutrik(r) Combo connector is a completely
balanced system. If you're connecting an unbalanced output to the monitor, be sure that
you're using PIN 2 for signal and have PIN 1 and PIN 3 tied together at the source
Could anyone elaborate on this please? Because I have no idea what it