Loud noise whenever i turn my speakers on

[nna2]

hi, whenever i turn my speakers on i get a quite loud buzzing noise, it varies in length/volume, and mostly happens the first time i turn them on within a few minutes, and whenever im turning the volume down, i hear a slight crackling almost like somthing is dirty

is there a way to fix this, i forgot the model of the speakers but there from labtek

 

[nna2]

bump
to add on there 2.1 speakers and the power cord goes into the subwoofer

 

[nna2]

last bump, anyone?