Hello guys,
I have a horrible problem. My home-studio devices consist in an Imac G5, an M-Audio 410 Firewire soundcard and two KRK Rokit 6 Powered monitors. From some mounths the monitors produce a really nasty noise, actually not really a noise but something like a square wave with a constant frequency. At the beginning this sound used to start as soon as the monitor of the computer was going in standby, but now it starts already when I switch on the computer. Working for hours with this saw in the ears is terrible. What do you think about this? does it depends on the computer on the sound card or on the monitors?
Notice that I tried to substitute the 1/4" balanced connectors, but without luck. Also notice that switching on the audio monitors, and not plugging the connectors to the computer, doesn't produce this irritating sound.
I really would appreciate your help.
Thank you in advance,
Gpp

You have a ground loop somewhere, something is not properly grounded.

how do you solve for ground loops?

The best way is running everything on 1 circuit, or at least a standard ground. If that does not work, use a transformer on the cable running to your monitors.