i need help with a noise problem
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Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=22788
Printed Date: May 12, 2024 at 4:43 AM
Topic: i need help with a noise problem
Posted By: genehewett
Subject: i need help with a noise problem
Date Posted: December 13, 2003 at 11:33 AM
i have a few questions about a noise problem with a install. i am mecp certified and have been in the industry for about 9 years. but i have a problem that i cant seem to find a answer for. i have a rockford fosgate 800@2 in a install that is runing a set for hifonics components and it has alternator wine in those speakers. the noise is there even when the signal cables are unpluged. i have changed the ground many times and relocated the amp away the big power cables. please help if you can. you can call me if you want or i will call you 706-333-7865 my name is gene.
Replies:
Posted By: Geeque
Date Posted: December 13, 2003 at 2:10 PM
What do u have the amp mounted to? Also did u run wires to each speaker or are you using the factory wires? ------------- Gary Kline
MECP Master Technician
Posted By: genehewett
Date Posted: December 13, 2003 at 3:02 PM
amp mounted to amprack mdf. yess all new speaker wires.
Posted By: defective
Date Posted: December 13, 2003 at 3:12 PM
probably power cable routing, or likely an actual problem with the vehicle. I've heard of vehicles being wired in such a way that the alternator will produce noise to the connections at the battery. What kind of vehicle is this? Might be the issue.... Also are the gains set too high..... i'm not trying to insult your intelligence. I know you've probably checked this already. -------------
Posted By: genehewett
Date Posted: December 13, 2003 at 4:08 PM
the vehicle is a grand prix about 98 year model. and i have checked the gains.
Posted By: auex
Date Posted: December 13, 2003 at 4:23 PM
IMO the problem is the amp you are using, rockford is great for bass but for mids and highs they suck. At any rate there is probably something going bad in the amp causing the engine noise, since you said it is still there when the rca's are unplugged this is probably the problem.
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Certified Security Specialist
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Posted By: sparkie
Date Posted: December 13, 2003 at 4:33 PM
Check the ground for the battery to the car's chassis. They are usually in need of a good cleaning to remove rust and corrosion. Make sure your amp's power cable is securely fastened to the battery with heavy gauge cable. Make the ground cable as short as possible and to a clean, paint free part of the car's body. Hook up test speakers next to the amp to determine if the noise is coming through the speaker wires.
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sparky
Posted By: Teken
Date Posted: December 14, 2003 at 6:13 PM
You may want to do a simple test on the vehicles alternator to eliminate that as the cause.If only one of the diode packs are faulty / shorted. It will emmit RFI / EMI into the vehicles electrical system.The old tech method of doing this without a scope, or a DMM that can capture the AC output.Simply take a florecent lamp, unplugged. Wave it over the engine compartment, and see if the bulbs come on slightly.You will of course have to turn off all the lights in the shop, as the emmitted light output is rather low.The wand method works in a pinch for those not having the equipement to do a diode check on the alternator.Even if the noise does not flucuate with engine RPM, does not eliminate the alternator as being the culprit, as some vehicles are able to produce a fairly steady DC output with 2 diode packs semi-blown.Just a thought.
Regards
EVIL Teken . . .
Posted By: forbidden
Date Posted: December 15, 2003 at 4:51 PM
Make sure the crossovers from the components are not mounted near any power wires or computers, found that one out by accident, still sounds like an amp issue though.
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Top Secret, I can tell you but then my wife will kill me.
Posted By: Geeque
Date Posted: December 15, 2003 at 6:31 PM
Maybe try a line driver?
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Gary Kline
MECP Master Technician
Posted By: livewire 1096
Date Posted: December 22, 2003 at 3:50 AM
i think you have a high restance ground on one of your speaker leads. diconnect one at a time until you isolate the lead the make sure it's not grounded. this usually happens a the leads on the speaker touching the basket or the car. ------------- livewire 
Posted By: genehewett
Date Posted: December 22, 2003 at 7:16 AM
the problem was decided to be the alternator rectefier. the only problem was i couldn't convince the coustomer of this. so i sent the coustomer to the mechanic that checked the alternator for more info.
Posted By: Teken
Date Posted: December 22, 2003 at 10:22 AM
Glad to know it worked out. How did you isolate the alternator as being the cause?
Regards
EVIL Teken . . .
Posted By: genehewett
Date Posted: December 22, 2003 at 5:49 PM
i didn't a local automotive shop did. i am good friends the guy that ownes the place and we worked togather to find problem.
Posted By: Teken
Date Posted: December 22, 2003 at 9:10 PM
Glad to see there was a positive outcome, regardless.
Regards
EVIL Teken . . .
Posted By: bpunzel
Date Posted: December 27, 2003 at 5:27 AM
Get a ground loop isolator, i had the same prob. ------------- 143.5 Spl
Posted By: genehewett
Date Posted: December 27, 2003 at 6:57 AM
i dont think that bpunzel read everything. the noise was there even when the rca cables were disconected. but thanks anyway the problem is fixed.
Posted By: Teken
Date Posted: December 27, 2003 at 2:05 PM
genehewett wrote:
i dont think that bpunzel read everything. the noise was there even when the rca cables were disconected.
LOL . . . *Must read all replies* 
Posted By: carriles
Date Posted: January 01, 2004 at 8:28 AM
I also have an alternator whine in my '02 Avalanche. The noise is still there when I diconnect the RCA from amp. I am useing large power and ground leads. They are running on the opposite side of my truck from the Stinger RCAs. My ground connection is only about 8 inches from the amp. But my distrubution block is only about 6 inches away. How far should these 2 be from each other? I never thought about this as a possible problem.
I have been reading this site for a while, and you guys are great!
If there are any other Avalanche owners with a built system out there, let me know 
Les
Posted By: genehewett
Date Posted: January 01, 2004 at 8:40 AM
Less it dont matter how close your power and ground cables are to each other. but it may matter how close thay are to your siginal cables. make sure the cables are at least 12-18 inches away from your power or ground wires. also check the resistance to the neg. side of batt. terminal from your ground point at the amp. the body ground at the battery is also important and is sometimes to small so try to upgrade it. there is a lot of questions about your system that needs to be asked and answered befour you can solve you noise problem but post questions and im sure someone will try and help.
Posted By: carriles
Date Posted: January 01, 2004 at 8:48 AM
Thanks Gene,
My power and ground wires are ran one the opposite side of my truck than the RCAs.
I was wondering how far my block should be from my amp.
Les
Posted By: genehewett
Date Posted: January 01, 2004 at 8:52 AM
that dose not matter just make sure that the connections at the block are good and tight. what i ment was where the rca's connect to the amp make sure that thay are as far away from your power and ground as possible. sorry.
Posted By: Overcranked23
Date Posted: January 03, 2004 at 8:46 AM
is your dist Block grounded or is it just a power block?? What kinda grounds do you have and how far apart are they??? ------------- don't fowl the track
Posted By: Julian59
Date Posted: February 01, 2004 at 12:38 AM
Gene If you hav't fixed your problem yet, Try this Real simple. Disconnect the noise source, "the Alternator". if the noise goes away, that's your problem. If not then you have a cold solder joint in the AMP or one of your signal processors Hope this helps Julian59
Posted By: carriles
Date Posted: February 01, 2004 at 7:54 AM
Overcranked23 wrote:
is your dist Block grounded or is it just a power block??
What kinda grounds do you have and how far apart are they???
It is just a distribution block,(Stinger) no ground
My ground point is about 12" away and goes directly to the body.
Les -------------
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