Speakers creates a buzzing sound

Sep 13, 2018
Hey guys, I wonder if you could help me here becuz I'm going nuts and I don't understand why the speakers make that buzzing sound when I plug the computer ..
Note: the buzzing sound decreases when I unplug the power source and the monitor ....
it decreases also when I connect everything but disconnect the speakers cable ...
I don't know what causing the (problem and I can't write well in English becuz it's not my native language)