First off, please don't respond with how much or little bass the factory radio and speakers have. My issue is that the mids and low end of sound started cutting out and then completely disappeared from audio. The stereo sounds like its playing through headphones. All speakers are working, but there's only highs. After seeing this was an issue with the stock radio, I replaced it with a Pioneer, but I have the same problem still. All highs, no mids or low end at all. All the speakers sound like tweeters. This is a 2007 model with the standard radio, not Bose with amp. Any ideas?