Hey guys, I have a Subaru Legacy Wagon from about 2004. I want some bass on my songs, but unfortunately, I'm not currently in a position to purchase subwoofers. The bass is decent as is, although it's not very satisfying. Are there any ways to boost the strength of the bass without subwoofers? Any help would be appreciated. Also, I sometimes hear a slight rattling sound when the volume gets up high enough. Are these the doors / other parts of the car rattling, or are the speakers going? Thanks.