Problem with KRK RP5 Monitors

 I can only guess here that the monitors are setting up the vibration in the computer case. If my guess is correct,then I would try to isolate the monitors from the desk. Either move the computer or use a foam insulator on the monitors. It could be a simple as tightening a cover or re arranging something in the case if the problem is being generated from the computer itself. The buzzing is likely metal on metal somewhere....try to isolate it.

 Most decent monitors are not apt to have a tweeter blow out unless you are driving them way too loud,and even in that case most of them can handle a lot and are protected to some degree. If you need to drive them to that level then they are too loud for mixing.