speaker problem
 

I have the bose system in my 8. anyways when i first got my car the front drivers side speaker was blown so right when i got that i had to get that fixed they put in new speaker to replace what was there. anyways after that everything was fine. it was not that far until i put in a after market radio and navi in the car. that was about a year later but then after a few months after the aftermarket system the driver side speaker goes in and out ....... and when i hit bumps on the road i hear thumps from the speaker (or static or something like that) and no its not the bass of the music. what seems is wrong with my speakers ?

the dealer wont look at it cause since i put in a new aftermarket system i void that part of the warranty of the car