dont know what happend but now im getting engine noise coming though my speakers. im running 3 amps and 2 ground leads from back to frount. what should i check. I tried putting a ground from my deck to the amps. it stopped some noise some what but not all. thanks

 

i would check and make sure your x-over freq is set up right i was getting what sounded like ground noise moved my grounds still had the noise turned my x-over down and it is now gone...check your amp grounds make sure you sand down to shiny metal too...hope this helps a bit

 

OK you need to find if it is the HU making it or a amp or other gear.Use a walkman to by pass each.Start at the amps,then move to the HU then in to the system on the way to the amp again.

99% of the time it is a ground loop giving the noise

One thing as well you have two grounds from the front.Are the mounting points the same on them?If not that can be it right there giving a loop.

 

ya because you cut off them freq. down,thats all you did its still there and on a O scope you will see it is.you are now missing your higher end freq.

also at higher power it will come thru in the end hurting your gear

 

I`ve been asked a few more thing on this so here Basic Car Audio Electronics
he does better with the words then me