PC speaker and toy pinball make noise at same time?

What would be causing the right side PC speaker to make a small popping/cracking noise and at the same time set off a sound/lighting affect from the toy pinball machine that is battery operated? I'm not the only one to witness/hear it happening. It's a random timing thing too. Would power surges in the walls be able to do this? Or is it something else? Also, the speakers only make odd noises when I run the paper shredder but I know why that's happening. I just don't understand the battery operated versus electrical connection thing going on.