Speakers Crackle when power is applied, why??

[Trek720]

When CPU is powered up my speakers make this awful crackling sound. (maybe 1 sec in length)
What could be the cause of this?

 

[Ryukumu]

Maybe the electrical outlet is overworked? I know that in the room I'm in I've got a ton of electrical gizmos plugged in across the room. Whenever the mini-refridgerator cuts in/off I get a loud pop on the speakers, then once the 'fridge is churning along there's no distortion at all.