really loud bass music. Like enough bass to make my mirrors vibrate. He normally HATES the car, especially going slow and stopping at lights. So for the running around town he normally screamed the whole time. White noise didn't really help, but he loves bass. Me, not so much. My DH has a "Bass Mekanik" CD that is what I have to listen to now... yay me.
If you want to hear Caleb's new fav song - check out this music video.