speaker distortion
 

I recently replaced the tape deck in my car with a cd head unit & changer.
However, the sound was distorting at the lower frequencies so I replaced the
front door speakers with 3 way speakers to improve the sound quality,
particularly the bass frequencies and to get rid of the distortion. The
speakers i put in were Kenwood KFC 1789, however the distortion is still
there. Any help/advice would be appreciated.