Im not sure if this is the right place to post this but I've had a pair of KRK Prokit 5s and just recently bought a new monitor. When I have the speakers plugged into my laptop and my monitor plugged in using a Apple VGA adapter there seems to be a buzzing noise out of the speakers. Its not too loud but it is distracting and annoying when I don't have music playing.
MacBook Pro (13-inch Mid 2012), OS X Yosemite (10.10.5)