i have a 01' trans am and installed a new head unit a few months ago, mainly for mp3 use. the bass is really erratic though from song to song with excessive vibration (not sure of the proper term for that.) the rear seat panels are dual voice coil subs that produce only bass. i tried different settings with the HPF and everything else, but it's not what i want. other than the bass, i'm perfectly fine with the sound. would it improve if i replaced the subs with single coil ones, or make it worse? any help would be appreciated.