system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why Do Slightly Opened Car Windows Make That Awful Sound

When I'm driving down the road, I can roll down a back window slightly and i get a god awful sound. It's rythmic and kills your ears. What causes this?
gpt
Air is trying to go both in and out of the window at the same time. If you crack open another window, the air pressure fluctuations will go away. 
Same as if you were pouring soda out of a 2 liter bottle; it comes out in rapid gushes. But if you poke a hole in the side, the sofa flows out smoothly.