My father has this old mp3 player that he really likes to use. He uses it in the car often but the only problem is that, sometimes, the interference is so bad you can't hear anything. This only happens in car. What's more is that this only happens in the car when the driver's door is closed. When the door is open, everything goes back to normal and you can hear whatever is being played just fine. This only works with the front door. When the driver's window is open, it doesn't work, either. I have no idea what could possibly cause this. It definitely has nothing to do with the player itself or our location. Other devices that can be used to listen to the radio (e.g. iPod, etc.) works just fine. What's up?