road noise in my speakers

[banks98stang]

ok so i have a pioneer deck with a 10 and amp in my stang. when the cars off and i turn the radio on with out the car started its fine . but once i start the car the speakers distort. i ran a better ground for my stereo and im still having this problem can any one help

 

[powershift46]

all speakers or just the sub?

 

[stangbang302]

i had a problem like this when i had my cavalier before drivin the stang. i had a amp hooked up but if you unhook the amp and run the speakers through the deck it'll work fine, it was wierd but once i researched and what not i had the amp hooked up and i unplugged my alternator while running the car and the stereo worked fine, never really found my problem tho so i just used the mono switch on the amp and ran mids and tweeters

 

[njoliver]

make sure ground isnt near any other grounds and make sure power wire isnt near spark plugs, using a clamping diode in circuit will also reduce EMI

 

[banks98stang]

all speakers or just the sub?

its just the highs the sib still hits
when the cars off the system sounds fine when i start the car the highs get crackly and distorted. i re did the ground and it still didnt fix the problem

 

[ID89GT]

You could add a coil of wire to I think the constant power wire? I am not sure, but you just wire in a coil of wire and it will go away, at least thats what I been told

 

[njoliver]

it might be a problem with powerwire, spark plug wires give off alot of electromagnetic fields these fields are probably coming in contact with your power wire, they make things to supress these sounds, (diodes). or you can try to run your wiring in a different route. somewhere in your system you are picking up EMIs you need to just reroute your wiring or put some sort of supressor in circuit.

 

[dgollem]

Check best buy, auto zone or a car stereo/alarm shop WalMart? They make filters that will elminated most EMI generated from an alternator if that is your problem. Cost any where from 10 to 100 dollars depending on the brand.
The link shows one

RMD: 007-0012 Pyramid NS-12 Car Audio 12 Amp In-Line Engine Noise Suppression Filter

This link does a great job of explaining what causes the noise
http://www.termpro.com/articles/noise.html