My Driver's side front speaker rattles hardcore, and other times it doesn't at all... If I turn the bass all the way down it doesn't rattle. Is it blown or just rattling for some reason? If so how do I fix this? What size is the front speakers for an Intrepid?

 

Probably blown... but depends on what your "rattle" sound is. "Rattle" isn't very discriptive.

I believe they're 6x9's in the doors, at least that's what my dad's has.

 

Try 6 1/2 and more than likely "rattle" means blown. The stock Infiniti speakers are easily and often blown because people get stupid with the volume. When you do replace the speakers dont be silly and try to replace them with standard Chrysler speakers, they will blow the second you turn on the system; always buy Infiniti speakers.