Anybody know anything about subwoofers?

if it works good plugged directly into your ipod ( I am assuming you used an ipod to rca adapter?) but not good when hooked to your stereo.....I would first ask what outputs you have the rca's plugged into in the back of your head unit? you need to make sure you have it on subwoofer outputs (or rear if there is no designated sub out labeling).

also depending on your head unit you should have multiple subwoofer controls for the volume and so on.

there isnt much to it but I am guessing that its one of the 2 things I mentioned.