I wonder if anyone can help me.
i have a powered sub in the boot, and run the cables thru the car myself, power down the left side from the battery and rca and remote cable down the middle from hu.
when i turn the gain up on the amp i get a lot of noise like an exhaust beat/ engine noise thru the sub.(dont seem to increase when revving throtle either)
i bought a ground loop isolator to see if this would fix it but it seemed to make it worse.
so i turned the gain down to hardly anything any the noise is just about gone but i have not much bass now.
oh and its not just this sub/amp i had the same problem when i had my older sub and amp in there aswell.
anyone have any ideas on this? or had the same problem?
any help would be great!

 

check the earthing point

 

ive changed the earthing point twice but still the same.
where is the best earthing point in the boot on an my05?

 

Is the earth cable the same guage as the power cable? Keeping the earth cable as short as possible often helps. Have you cleaned up the earth points in the engine bay as well?

 

Yeah the cable is the same gauge, even thicker maybe as i changed the one that was in the kit. and its not that long either.
no i havent really thought of that as the car is only 2yrs old. will have to try.
do you think it could be the remote cable interfering? its only a tiny cable tho?

 

Jap cars regardless of age seem to have crap earth points in the engine bay.

 

Poor sheilding quality on the RCA leads.

Build your own, and route them separtely to the power cables.

Or get a head unit with hi-volt preouts that gives a better signal to noise ratio, so the amps don't need to run so much gain.