Why do my subs vibrate when my volume is low ?

Question

i had rockford fosgate subs with polk momo ampppppp. its getting bass thats interfering with the song . like when iput the volume low the subs are still rumbling and its bugging me really bad can it be bad ground? battery? its pissing me offfff! so pleasee help me it would be much appreciateddd . if you answer my question please know what your talking about :D THanksssss

this is the exact subs http://www.garinet.com/cgi-bin/gkwebstore_shopping.cgi?ACTION=VIEW_PRODUCT&DEPARTMENT_ID=49&CATEGORY_ID=302&PRODUCT_ID=988&SOURCE=new_release_within_products&LANGUAGE=e

and here is the amp

http://www.polkaudio.com/caraudio/products/monoblock/amps/c500_1/

umm i dont know much about amps so if you can like help me out with the settings for the amp that would be awesome :)

Answer 1

Could be quite a few things; first unplug the RCA cables from the amp and see if it is the AMP that is creating the distortion.  the Distortion (or the unwanted Bass) May be caused by a Faulty Subwoofer Amp.  Could also be wires touching inside the speaker box (probably not, because then the amp should go into protection).  If the distortion stops after the RCA cables are disconnected, you know it's either faulty RCA cables, or a Bad signal coming from the head unit.  Is it on every song / cd / radio station?  Do you have the amp power cable hooked up to the battery or alternator?  some swear by hooking up to the alternator, i disagree.  are you running a capacitor?  Does the distortion change with the pitch of the engine? (when you drive faster - does the distortion get louder or change frequencies?)  there are many possibilities why this could be happening...  one more thing, does the distortion sound through the interior speakers as well? (all speakers but the subs?)   What's your gain set at?  shouldn't be cranked more than halfway.  Do you have your subs wired in a series or paralell?