So I've got this computer...

It is plugged into a 6-outlet strip. In this 6-outlet strip are plugged my computer, my monitor, my alarm clock, my printer, my modem, and a black light.

This 6-outlet strip is plugged into a wall. This wall is one of four walls defining the perimeter of my room.

I have a fan called Hawaiian Breeze. It is plugged into an adjacent wall, directly into an outlet of its own.

When I turn this fan off, I hear a noise through my USB speakers, which are plugged into my computer. This noise is the same noise I hear when removing a flash drive or other device from my computer.

What the hell is going on?

Edit: The black light also does this, but it's less weird, considering it's plugged into the 6-outlet strip. Still... I don't have the slightest clue why it would do that, either.

The "bla-dunk" sound windows makes? That is weird. No idea how it could happen though.

The best answer I can think of is magic...