Yesterday when I started driving, everything was fine. Then about 20 mins into my drive my driver side, front speaker starts making this awful sound. Im thinking its the woofer because it only makes the sound when there's bass. So I just turned it down and off for a few mins and turned it back up and it would be okay for a few mins then do it again, did it on the drive home too. But today it wasn't doing it (maybe I had the audio lower knowing it would probably do it) Im not a person who cranks my audio so its not like I blew it..anyone else experienced this? I guess ill be taking it to Ford if it does it again.