# grounding post



## Jaycruze (Jul 11, 2011)

Hi all,

I'm getting a high pitch humming sound from my amp when i turn the car on and it think it is because i currently have it grounded on the same post as what looks like is the right/rear tail lights. (i didnt notice this sound before because i had the amp set for super low frequencies)

I want to ground to another post but i dont have the right size nut for the post.

Does anyone know the size/thread size of the nuts for the grounding posts?


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## titan2782 (Nov 4, 2011)

I'm imaging your tail lights dimming on and off to the beat of your music


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## amalmer71 (Apr 5, 2012)

Aftermarket HU or stock?
If stock did you use a LOC of the one built into the amp?
What amp is it? Brand and model?
What size power wire and ground wire are you using?
Is the power wire running on the same side of the car as the patch cables?

The more descriptive you are, the more help you'll get.

Basically, I'm leaning toward it being an interference in the patch cables (the signal cables/wires, whatever you choose to call them).
First, disconnect them and see if the humming goes away. If not, at least teach the amplifier the words so it can sing instead of just hum. LOL

Does it get higher pitched with engine RPM?


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## Jaycruze (Jul 11, 2011)

It doesn't change when im driving. I can hear it get louder when i press the brake down though.

It doesnt make the sound until i turn the car on. I havent tried pressing the brake while the car is in ACC mode.

It's a 600watt amp with a wiring kit, I grounded the loc and amp in the trunk at the same spot where the brake lights are going. (i think its the brake lights anyway)


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## XtremeRevolution (Jan 19, 2012)

Jaycruze said:


> It doesn't change when im driving. I can hear it get louder when i press the brake down though.
> 
> It doesnt make the sound until i turn the car on. I havent tried pressing the brake while the car is in ACC mode.
> 
> It's a 600watt amp with a wiring kit, I grounded the loc and amp in the trunk at the same spot where the brake lights are going. (i think its the brake lights anyway)


I have the same problem. My power wiring is run on the driver's side, and my RCAs and speaker wire on the passenger side. I'm getting the exact same sound you are. The wiring for the brake light is run alongside the RCAs and the RCAs may be picking up interference. However, I'm not sure if that's the case. The noise does not change with RPMs so it's not alternator whine related and not a grounding issue. The factory radio produces some static noise on its own. 

Try lowering the gains on your amplifier, and let me know if the buzzing quiets down. If it does, it's an issue with the head unit, and you may want to look at finding a new ground for it.


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## Jaycruze (Jul 11, 2011)

Actually the sound does go away (gets too quiet to notice) if I lower the Gain on the amp... I always have the gain above 75% 
(i pretty much crank it.)

Ya i want to try another ground... but i need to find a nut that fits the post lol 
((ohhh you mean find a new ground for the factory radio))hmmm

extreme you're tapped in with one of those PAC converters right?

I actually did it a weird way, I have a Stinger LOC but i have the LOC in the trunk, grounded at the same spot as the amp.

I tapped speaker wire to the big wiring spot up by the hand brake and ran that tapped wire all the way to the trunk and hooked it up to the LOC there.

I have the tapped wire running along the right side of the drivers seat and then turns over to the right side of the car and back.. The amp power is running along the left side.


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## XtremeRevolution (Jan 19, 2012)

Jaycruze said:


> Actually the sound does go away (gets too quiet to notice) if I lower the Gain on the amp... I always have the gain above 75%
> (i pretty much crank it.)
> 
> Ya i want to try another ground... but i need to find a nut that fits the post lol
> ...


Good, then you confirmed my suspicion. This static noise is coming from the factory radio. You may need to find a new ground for that radio, and hope that it helps. The kind of PAC used won't make a difference here as the problem is at the source. I haven't thought about this a whole lot yet, and will need to get some feedback from others before attempting anything. You would have to cut the wire at the harness behind the radio to run a new ground wire.


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## amalmer71 (Apr 5, 2012)

Make sure the outer ring of your RCA's going into the amp and into the LOC aren't touching the case of the amp or LOC (i.e. pushed in too far). This can cause feedback through the RCA's, especially if you have the amp mounted on the chassis of the car.

It may be as simple as using a ground loop isolator mounted for the RCAs. I'd provide a link to one that I know works well, but I just got a slap on the hand for providing links to outside retailers.


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## XtremeRevolution (Jan 19, 2012)

amalmer71 said:


> Make sure the outer ring of your RCA's going into the amp and into the LOC aren't touching the case of the amp or LOC (i.e. pushed in too far). This can cause feedback through the RCA's, especially if you have the amp mounted on the chassis of the car.
> 
> It may be as simple as using a ground loop isolator mounted for the RCAs. I'd provide a link to one that I know works well, but I just got a slap on the hand for providing links to outside retailers.


It's not the RCAs. I've verified this as well as another member. The static is coming from the factory deck.


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## GoldenCruze (Dec 18, 2011)

Just a thought here....

An old CB'ers trick is to hookup and ground the radio the vehicle battery. The battery acts as a huge filter that prevents humm and popping from the ignition and other systems.


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## Jaycruze (Jul 11, 2011)

I'm going to try a ground isolator this weekend, can't hurt to try and they aren't that pricey anyway.

I really want to avoid messing around with the factory radio if I can.


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## amalmer71 (Apr 5, 2012)

XtremeRevolution said:


> It's not the RCAs. I've verified this as well as another member. The static is coming from the factory deck.


Verified this? You drove 500 miles to Toronto?

Look. I'm just giving him things to check to eliminate where the problem can be coming from. Isolation leads to elimination. Why do you try to criticize me, hidden behind a snide remark, for trying to help?

Funny. My wife's car has the same factory head unit, and her car doesn't have any "hum". I guess it knows the words. 

JBL 500 watt monoblock with a Pyramid LOC (That's right. I said Pyramid) and an Alpine 8" Type-R. 
No hum. No whine. No cracking. No popping. Just pure, clean, unadulterated bass.


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## XtremeRevolution (Jan 19, 2012)

Have you upgraded the front speakers in your wife's car? The static is coming from the front, not from the sub. It's not an isolated incident. 

If he reduces his gains and the static goes away, that's a clear sign that the static is coming from the signal source, and given two of us have had this exact same problem and ruled out the RCAs as not being the problem, it's going to be either the PAC harness or the factory deck.

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## tecollins1 (Nov 6, 2011)

amalmer71 said:


> Verified this? You drove 500 miles to Toronto?
> 
> Look. I'm just giving him things to check to eliminate where the problem can be coming from. Isolation leads to elimination. Why do you try to criticize me, hidden behind a snide remark, for trying to help?


No need to take it personal...
He's not attacking you he's just crossing off something that's already been tried.

I'm the one he's referring to. Where all three of us are having the same symptoms. I, on my side have already upgraded the RCAs with high quality ones and it did not solve or diminish the problem.


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## NeonRyder (Jan 3, 2012)

Cool! I thought it was something I did wrong on my install! But apparently not!


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## amalmer71 (Apr 5, 2012)

OK. Let's think about this for a second...

1.) I never said it was the cables that were causing the problem. I was simply helping the OP figure out if there was a DIFFERENT source of the noise other than the point of where he grounded the amplifier. You know... teach a man to fish... blah blah blah.

2.) If reducing the gain pot on the amp eliminated the noise, can you guess where the noise was coming from? Since amplifiers only reproduce what's input into them, turning the gain "up" increased to amplifier's input sensitivity which allowed electrical interference in. It doesn't come in anywhere but through the patch cables. I was just suggesting he check to ensure there weren't OTHER common problems which allow electrical interference into the amp. By ISOLATING EACH COMPONENT (not "isolated incident") you can eliminate each source, individually (Quit twisting my words).

While turning the gain down may eliminate the noise, it isn't necessarily fixing the problem. It's simply compensating for it (i.e. sacrificing). I could go on and on about possible causes of how electrical interference is introduced into a car's audio system, but evidently someone seems to have this uncanny desire to shoot down any suggestions I make to help the OP and any future readers learn how to find the source of the problem, opposed to just making assumptions of where it's coming from.

tecollins,

You changed the patch cables, then turned the gain down, correct? How do you know if changing the patch cables didn't allow you to be able to increase the sensitivity of the amp without interference, compared to the old patch cables? You didn't isolate each possible source of the problem prior to changing the patch cables, correct? You just turned the gain on the amp down (after replacing the patch cables) until the noise was inaudible and called it good? BTW, which isn't getting rid of the electrical interference. You compensated for it.

If people are turning down the gains of the their amplifiers, and happy with that band aid, then so-be-it. Who am I to help, right? After all, I only do this kind of stuff every day. I can't tell you how many cars we get in every week of someone who tried to install something themselves and ended up with either destroying something, introducing a lot of electrical interference, or simply can't get the stuff to turn on. We get to figure out what they did wrong, then fix it. Some of it's not even anything they did wrong, they just don't know what to do "right".


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## XtremeRevolution (Jan 19, 2012)

Adam, the problem is electrical noise coming from the factory radio. I guess it could be the PAC harness, but that would mean everyone's harness is defective because we're all hearing it. It's not the RCAs, it's not the amplifiers, it's not the amplifier grounding. 

If you want to help, help us figure out how to stop the factory radio from creating static/electrical noise.

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## Stlucky22 (Sep 28, 2012)

I have the same thing. I have only replaced my rear driver side 6 1/2 (as well as a sub but the buzz is only heard at higher frequencies) and there is no buzz when I initially turn on the car. The buzz is heard if I press the breaks and continuously once put in gear, but louder. It doesn't increase in sound when I turn up the volume, nor does it go away when I turn off the radio. It nots that bad, unless my music is off. The increased door chime is more annoying than that, but at any rate that's only one speaker with the gain under half adjust. I am afraid of replacing my front door speakers now. If I were to multiply the buzz times 4, I feel it would then become a real problem. I've done very little troubleshooting since I have seen a few others here with the same issue, but I'm all for ANY help or advice. Let's just stick to this COMMON PROBLEM and SOLVE it. I have a ground loop isolator and they are useless. I think it's something to do with my PAC harness ground, but my install still needs some modification. Trying to ground or "reground" the stock unit is new territory for me and I think should be the last option unless we know for sure thats all it could be.


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## XtremeRevolution (Jan 19, 2012)

Stlucky22 said:


> I have the same thing. I have only replaced my rear driver side 6 1/2 (as well as a sub but the buzz is only heard at higher frequencies) and there is no buzz when I initially turn on the car. The buzz is heard if I press the breaks and continuously once put in gear, but louder. It doesn't increase in sound when I turn up the volume, nor does it go away when I turn off the radio. It nots that bad, unless my music is off. The increased door chime is more annoying than that, but at any rate that's only one speaker with the gain under half adjust. I am afraid of replacing my front door speakers now. If I were to multiply the buzz times 4, I feel it would then become a real problem. I've done very little troubleshooting since I have seen a few others here with the same issue, but I'm all for ANY help or advice. Let's just stick to this COMMON PROBLEM and SOLVE it. I have a ground loop isolator and they are useless. I think it's something to do with my PAC harness ground, but my install still needs some modification. Trying to ground or "reground" the stock unit is new territory for me and I think should be the last option unless we know for sure thats all it could be.


I will do some work when I get my car back next week to re-ground the PAC harness and see if that will make a difference. My initial guess is that it won't, but it's worth a try. It's either the head unit or the PAC harness.

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## Stlucky22 (Sep 28, 2012)

Just as I feared. I ordered a phone/RCA adapter and I'm still getting the buzz when I press the brakes. It has to be a grounding/ wiring issue as I completely bypassed the PAC harness and head unit when hooked up through my phone. Tomorrow I will start trying to isolate and/or eliminate the buzz now that I'm convinced it's not the PAC or headunit just to give an update.


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## Jaycruze (Jul 11, 2011)

When you guys ground your amp in the trunk are you stripping the paint from the grounding area?


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## XtremeRevolution (Jan 19, 2012)

Jaycruze said:


> When you guys ground your amp in the trunk are you stripping the paint from the grounding area?


I sanded the paint off on mine.

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## tecollins1 (Nov 6, 2011)

XtremeRevolution said:


> I sanded the paint off on mine.
> 
> Sent from my myTouch_4G_Slide using AutoGuide.Com Free App


Same.


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## Jaycruze (Jul 11, 2011)

just an update,

I have tried moving my 2channel LOC to the left rear door *both channels on one speaker*. (i previously had it up by the bundle near the clutch pedal)
I have moved my amp ground to another factory post (sanded it down)

No change, i still get the hum ONLY when the car is on. If i turn the key in acc mode it sounds perfect no hum at all.


I'm wondering if i try to shield my power wire better if that would make a difference, All of the stock speaker wire merges at the clutch area, which is right where my power wire is going through the firewall to the battery.


***Edit i forgot to mention, i went to a car audio shop because i was going to get a noise filter (ground loop isolator)

They let me test 2 of theirs and all it did was make my amp so quiet that you could barely hear it.


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## titan2782 (Nov 4, 2011)

Has anyone suggested the alternator? I've been in a few cars that had an alternator cause interference with the stereo. Another suggestion would be to use one of those big-a** audio capacitors. Capacitors not only prevent dimming during hard bass hits, but are also used as filters.


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## 1990tsi (Apr 29, 2011)

I have to add my 2 cents, i'm using the factory head unit, speaker level input with signal sensing turn on into an LC2i with my power wire running beside the speaker level wires from the hood release to the trunk. i have a 20" ground wire to a point on the drivers side of the trunk sanded down with a rolox disc. using a single Polk full D class 5 channel for my mids tweets and sub and i have no noise, no hum, no pop, nothing. i'm even taking my LC2i ground from the negative terminal from my amp., same with the 12v+ from the amp, and the LC2i is providing the remote turn on for my amp.

not sure why, but no noise. the amp is a polk d5000.5


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