They have a midrange and high frequency driver on the doors for your listening pleasure. Having those drivers closer to you head (rather than down by your feet) you'll hear those frequencies without any phase cancellation that you get when the mid and high frequencu drivers are down by your feet. I'm not too impressed with the low frequency quality. It gets a little boomy for my tastes. Having said that I prefer it over the Bose system I had in the retal for a few weeks. If you're a "big boom" car stereo guy, you won't most likely won't care for it.