Safe
I have the same problem as you do, its fucking annoying. From what i have gathered this problem come under Electromagnetic interference, usally this problem is caused by the power cable in which you are using to power you laptop or pc. If you have a laptop you can test this by simply unpluging the power cable and if your problem is the same as mine, that intensly annoying buzzing sound will vanish and peace will be restored!
After i did this, learnt that the interference is coming from the power cables i proceeded to google the problem, doing this found me this website
http://www.pcuser.com.au/pcuser/hs2.nsf/lookup+1/931993547A4099C6CA256E5E008307B5
helps alot, although it doesnt really resolve your problem it tells you what things might be causing it, from here you can go on to test diffrent things and find out what it is thats causing the buzzin and what helps to get ridda the buzzin.
unfortunatly i never mangaged to fully resolve my problem, from what i gather i either need to new laptop or just get a desktop pc, this way there shouldn't be any power cable interfernce what so ever.
for now i bought these little things, but for the life of me i cannot remember what they are called, but you can buy them in any electronics shop, they are small cilinder shaped magnets that you coil you power cable around, i have two of the and the buzzing has been reduced greatly, but its still there and blatent as ever, but for you this might completely remove it.
by the way, if you do find a total fix for these please message me or somthing, learning to produce with a constant noise like what i have is like trying to learn to swim in a straight jacket, pretty dam hard.
hope this helps
(also i have the same speakers as you, rokit 5's, maybe its a problem that krk know about and by ringing they might be able to help, but thus far i have not bothered ringing them)