Monitor interference or busted component?

I've got a pair of 3in monitors that have been serving me well over the last 3 years or so.
I've had to move my studio into the basement for client work (from my bedroom, naturally), and everything was working fine until just recently after I had to push my setup against a wall.
 
For some reason, just lately, my monitors have started making a light crackling noise, not unlike the sound of wood burning in a fire.
This happens regardless of whether they are plugged into my interface or not.
It *seems* to be some sort of interference or something with shielding, as the volume of the sound is MUCH less now that I've plugged the monitors into their own wall socket and moved my internet antenna further away. So far it seems to be working fine as before.
 
Anyone with some knowledge about this who could possibly assist me so that this issue DOESN'T persist any longer than it needs to for me to learn how to solve it?

Make sure all your connections are 3-conductor, and if you're using a power strip make sure everything's plugged into the same strip. Pick up an electrician's tester at the hardware store - they're just a few bucks - and make sure the basement outlets are properly wired and grounded.