Interference, Please HELP

[moggs]

I have recently fitted a sub and when i first fitted it the amp was sending Mid, Bass etc to the sub. So i bought a crossover to sort it out. when i put it in there was alot of interference but only when the engine was on, After playing around with different earth places (The crossover requires both a power & earth)i took it back to the shop. they were stumped and ordered me a new one but i have the same problem with this new one. it only happens when the crossover is in line so i guess it is down to this. Ive changed the RCAs but its still the same. Any help would be wicked. Cheers

 

[derv]

cross-overs are an arse for interference! i had one before cus there were no filters on the amp itself but i couldnt get rid of the humm through the speakers. I found the only way to illiminate the hum was to take the cross-over out!

 

[Mad_Marky]

One thing you can try is to connect the crossover to the same grounding point as the head unit. Just run a loose wire to start off with to see if it makes a difference. You can also buy ground loop isolators which can often help.