Not just bass. Lyrics and treble too. I can have the bass all the way down. Only the 5-1/4s too. I have it now so my fronts are turned down half way. But when i turn it up its very distorted. I changed everything at the same time, and yesterday i tried a different radio ( because i bought my gf the same one) and the same thing with hers. In her car everything sounds great. She has a 2 door saturn with aftermarket speakers as well. So it has to be either wireing, or what you said about the space in my door..? Any one else have this problem?