Look on the back of the studio monitors. I have the Rokit powered 5's I have stereo (balanced) 1/4 (quarter inch) jack to XLR but you can use 1/4 jack to 1/4 jack, I found RCA too noisy too much interference. I also use a Focusrite Scarlett 2i2 USB audio interface which has 1/4 jacks balanced outputs for left and right studio monitors. My setup is mainly for ableton live lite and a few software synths and a few plugins. I have not been able to isolate interference and remove it completely, there is always some form of electromagnetic interference. Some have suggested ground loops but my setup will suffice.