Aces High Bulletin Board
General Forums => The O' Club => Topic started by: Lazer on July 11, 2004, 02:56:23 PM
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Here is a question for anyone good with car audio...
I hardwired my own CD player into a BMW, because I didn't feel like paying an unreal amount for a wireharness, and now I seem to have static sound in my speakers, ONLY when the car is on/in motion.
If you play music with just car power on, and no engine running... it sounds fine.
Any ideas?? :D
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Yeah, Don't do your own wiring.
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Sounds like you have ignition noise. You need to check that the head unit has a solid ground to begin with. Use an Ohm meter to check that the ground is good.
I have solved many cases of motor noise, it's a step by step elimination process, but begin by checking that ground.
Do you have a seperate amp or amplified speakers?
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did you run the power for the CD player through the radio circuit or it's own? I believe the radio circuits are insulated from feedback from your ignition system, while others aren't.
it was explained to me a few years ago but I really wasn't paying much attention at the time, hopefully someone with more usable knowledge will reply.
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No amp.. I don't even have car speakers in ATM.. they are in the mail.
I hooked up a pair for Awia home audio...:rolleyes:
Where should I check for the ground connection?
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You need an OHM meter. Then pull the radio out of the dash, test between the radio chassis and a good, metal section of the car....a good spot is the door hinges/bolts/screws in running boards...etc. You should read very close to 0 ohms resistance.
If you don't have a meter, get some wire and attach it to the radio chassis at the back brace, and then connect ( touch) the other end to a good metal section of the interior or dash while the car is running. Test different areas and listen for the noise as you go. Also, move the radio in and out to see if the noise increases or decreases.
It's almost always a ground problem with a head unit and no amp. Very rarely , it can be the head unit itself.
Also, if the car is in a garage, pull it outside. Ignition noise can be a lot worst from an enclosed area.
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How should I fix it?:D
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Originally posted by Lazer
How should I fix it?:D
make sure it has a good ground, pretty much in a nutshell. If you still have the noise and do not have the experience or patience to trouble-shoot the problem, you need to take it to an installer that knows what they are doing.
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I think I got it now.. Thanks NUKE/Apathy :D
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they make good ground filters that are less than $20. All they do is filter out all that noise to ground.
Next time use a wiring harness. They arent that expensive and they save you ALOT of headaches further down the road.
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Originally posted by Lazer
I think I got it now.. Thanks NUKE/Apathy :D
if you want, email me ( profile)
I'll call you and help you if you would like.
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Im restoring an 87' BMW, and it seems difficult to find a wire harness for it.
I know the benefit of a wire harness, have a little newer BMW and I could find that harness, and believe me, it was much easier than this is... :D
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also the antenna can pick up engine frequiency, install a good antenna.
NUTTZ
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I just thought of this:
Whatever you connected from the car's harness to the radio's ground wire.... cut that connection, leaving the antenna plugged in. Listen. Is the noise gone?
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I know in the old days when I was into that sort of thing all we usually hadta do to cure it was to spend a couple extra bucks on Silicone sparkpplug and coil wires.
Worked every time
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As others have said sounds like a ground problem. Depending on your setup, a ground loop isolator can eliminate the noise. You can get them from Radio Shack.
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Originally posted by Lazer
Any ideas?? :D
Rip out the cat, put three inch pipes on it and you wont even notice the static.
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BTW, Nuke used to install car audio professionally, his family owned a shop here in the PHX area. He has done all the installs w/ me on my vehicles. I have a ground thumping system in my 'vette that he and I installed. It developed some ignition noise... we finally narrowed it down to a bad coil.
If you haven't tuned up your vehicle in a while, now is a good time. Old ignintion parts can cause spark noise regardless of how solid your install is.
Good luck!
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Thanks.. Im going to go try and snip that ground wire now and give it a shot.
As far as that "cat" goes... lol you don't want to know ;)
Have a hole that covers the entire underside of it. :D
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Originally posted by Saurdaukar
Rip out the cat, put three inch pipes on it and you wont even notice the static.
my kid uses the revers approach, with that new amp you can hardly hear the odd noises coming from the engine.
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http://www.radioshack.com/category.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F007%5F002%5F004%5F000&Page=1
Most likely it's alternator whine.
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Noise filters, ground loop isolators, voodoo and human sacrifices. NONE of this will eliminate spark/ignition noise if the wires, coil, plugs etc need changing.
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It only does it with certain CD's though....??:confused:
Seems to get better when bass is turned down too... But I really don't understand why some CD's do it and some don't...?
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nothing??? :D
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Lazer, I could address this but I'm sure Nuke will look at this thread when he can. He's a wizard at this stuff so I'll let him guide you.
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Sounds good... just doesn't click for me why it plays static on random CD's.:rolleyes: