# alternator whine help me get rid of it. already tried many things



## matthewo (Jan 31, 2008)

ok, well i have been threw a good amount of testing and regrounding and rca changes ect. there is still alt whine. i have a pontiac g8 and the alternator is very whinny in the morning by itself when starting the car up, so that cannot help.

anyway. my system is the stock head unit with the car, high level outputs to a audison bitone processor, then onto short nice rca cables which goto the amps. not run near power cables.

i will go threw the things i already tried:

moved ground
tested other amps
big 3 upgrade
lowering gain
tried cheap line output converter, it was much worse then the sound processors. my 3sixty.2 was a little less alt whine, and the bitone is even better, but i have to run my amps at 0 gain, and i dont like to do that because i have to turn the headunit all the way up to get good sound, and the stock headunit probably distorts up that high.

moved the head units ground to the grounding block for the amp, yet the head unit's case must be grounded because it works with no ground wires hooked up. this kinda sucks cause i would have to remove the whole unit and try to find a way to isolate the whole chassie from the car. if that was even the problem.

i have one of the power wire noise filters, my deck has like 3 power inputs because it also controls the a/c climate and all. im kinda hesatent about chopping up the harness even more for something that probably wont help. has anyone had any luck with these power noise filter for head units. its a little box with what seems to be a transformer in it and a small resistor. you put the 12 volt in and run the output to the headunits power, and also hook up a ground.

i need help, i have a high quality system but the whine is killling mee


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## dalucifer (Oct 8, 2007)

I would start testing your amps and processor out of the car... I had a similar issue as you(going threw all the same steps as well), then I changed both head unit and amps then no more alt whine.


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## matthewo (Jan 31, 2008)

well its the head unit. may people have this problem in the car, i just dont know what i can do to stop the head unit from making the noise


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## VP Electricity (Apr 11, 2009)

matthewo said:


> moved the head units ground to the grounding block for the amp, yet the head unit's case must be grounded because it works with no ground wires hooked up. this kinda sucks cause i would have to remove the whole unit and try to find a way to isolate the whole chassie from the car.


A HU can ground through the antenna connection also... and perhaps the illumination lead (I've seen ungrounded HU work through the ILL ground until the parking lights are turned on and the ground turns into 12V+ on the ILL lead). 

No matter. the HU will always use the best ground. That's where ground loops come from. 

The power line filters work when they work, but you should have heard it before in the OE system if the HU was passing powerline noise. 

So the Audison has no noise until you gain up the amps? Have you gotten on the phone with a bit one owner who can ensure over the phone that you are getting the right amount of output gain?


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## mda185 (Dec 14, 2006)

Are you using coaxial RCA cables from the Head Unit to the Bit One or are you using twisted, shielded pair RCA cables? In some cars, this make a huge difference. There are ground currents traveling through the chassis at all times and in some cars, these ground currents radiate significant energy that will get into a regular coaxial RCA cable. BMWs with batteries under the back seat are probably the worst offenders because there are always large currents flowing between the battery and alternator. Twisted shielded pair wiring will help improve the signal to noise ratio of the run from the HU to the Bit One.

If your OEM HU has its negative outputs at the same potential as the 12 
VDC ground of the car, this will also give problems. Twisted shielded pair wiring will not help if that is where the noise is getting in.


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## NOFATTYS (Jan 5, 2009)

Since a few of you either missed what matto was saying, or misread him, let me reiterate whats going on. 

The G8 factory headunit must stay in the car because it also controls the A/C, so there is no way around that issue, besides installing a seperate headunit in a fabricated location atop the dash, which looks kinda bleh, or in the glovebox, which just over complicates things. 

Second, since it is a OEM system without aux outs, there are no RCAS being run from the headunit to the BitOne processor, it is done through high level outputs. 

The whining sound was definitely coming through the speakers before any processors or amps were hooked in, my best guess from reading posts on two boards was that the headunit was the offender, but even with the power to the unit off, the whine is still there. Our cars do have an lcd screen that still displays some information when the power is off to the radio and HVAC unit, so maybe illumination lead is the key. 

Personally, I didnt use the headunit at all in the equation. I terminated all wires coming out of the unit that ran to speakers or Onstar and I utilized a 12v to remote turn on my amps with a short timer to prevent pops, and connected a high quality PMP directly to my processor. The result was no whines!


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## mda185 (Dec 14, 2006)

NOFATTYS, What is a PMP and what unit did you use? If you terminated the high power speaker outputs from the head unit, how did you get the signal to the processor? Are you saying you terminated the speaker outputs into some kind of resistive load and took the signal going to the processor from this termination point?

BTW, twisted pair wiring is not just used for pre amp level signals. BMW used it for many years for the high level speaker signal going back to a booster amplifier in the trunk. They also used it for the amplifier to speaker runs. Without it in both locations, there was terrible alternator whine.


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## matthewo (Jan 31, 2008)

well, the whine is aways there, its just less noticable when the gains on the amps are turned down. turning the gain up just boosts the whine. but i need to run my gains up more then bare min. because i have to turn the head unit up really loud to get enough signal the stock unit puts out power at 2 ohm so it really doesnt put as much signal out as some factory units.

anyway i got the gains set where i like them now, and its got some whine. you can deffenatly hear it when the volume is at 0 and the windows are up.

if i turn off the stock stereo but leave the bitone on, the whine goes away. i like your idea about the antenna lead, thats probably whats grounding it. but not sure how to fix that if i need an antenna?

nofattys is a member at the g8 board with me where a lot of members have the alt whine problem. the whine is even there a little with the cars factory with no audio modifications. but when you start putting amps and boosting the signal the whine really comes alive. i think what nofattys is saying is he runs some sort of media player which doesnt even run threw the stock stereo, which is a nice idea, im am actually getting one, the old rf omnifi digital media player, i will run it directly into my aux input on the bitone for my mp3s, i will be using this a lot of the time, but i still want to have my stock radio and no whine to listen to the radio and cds...


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## matthewo (Jan 31, 2008)

also the high level or speaker level inputs im getting out of the factory harness at the trunk of the car, these wires do pass close to the battery, maybe i will try and move them a little


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## NOFATTYS (Jan 5, 2009)

oh sorry...PMP = portable media player. I am using a Cowon S9 and blue jean cable's 1/8" to rca cable directly into my Audiocontrol DQL8. 

The Cowon S9 has a sweet radio built in as well. I sat in my car before terminating the stereo signal to the speakers and listened to the car radio transmission vs the Cowon Radio Transmission. The cowon surprisingly played all the local stations without a hit of static. the only station it had trouble picking up was hot 97.1 which is a rap station based in manhattan and im 70 miles away, so im happy with the results.


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## kustomtunes (Jun 20, 2009)

are you running component speakers with passive crossovers, if so check the mounting location of the crossover, some are notorious for picking up radiated noise, if they are mounted near anything electrical, try to move them to a different location away from the possible source of the noise. after everything else you've tried, this might be your culprit. good luck, hope this helps.


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## mda185 (Dec 14, 2006)

You say there are three power inputs to the HU. Usually there is one power line that is always hot and one that is switched with the ignition. If you can identify two that are specifically for the radio, I would recommend that you try to power the HU from another 12 volt car battery that is not hooked up to your car. Hook the ground wire from your HU to the external battery too. Start the car and see if the whine is still there. If this eliminates it, the noise is coming in on the power line and a power line filter should help.

If the noise is still there, try removing the HU from the dash and unplug the antenna to isolate the ground of the HU from our car. Power it from the external battery, start the car and see if the whine is still there. If it is gone, you have a ground loop problem because the ground of the radio is at a differential voltage level than the grounds for the Bit One and amplifiers. If you have a ground loop problem, there are several ways to approach it. First find out if the negative speaker lines are at ground potential. Measure the resistance between the speaker negatrive leads and the radio ground. If the resistance is zero or very low, you need to isolate the signal ground from your car's electrical system. There are ground loop isolators available for this purpose. Radio Shack used to sell a cheap one but I would not use that with your system. Try Navone Engineering to see if he sells a high quality one. If the speaker - signal is not grounded, you have a high output amplifier on the HU and the noise should be on both the positive and negative lines. 

In theory, a differential input amplifier should be able to cancel this. I would expect the Bit One to have a differential input. This is clearly not working to eliminate the alternator noise. That suggests that you have a combination of ground loop noise and radiated noise coupling into the wires from the HU to the Bit One. That is where twisted pair wiring can help. It made a dramatic difference on my 95 BMW 525 wagon. I put an Alpine HU in mine with coax RCA cables running back to some old school Audio Control EQX's and Soundstream amplifiers. I had terrible alternator whine. If I bypassed the EQX's and plugged directly into the Soundstream amps the noise was reduced. When I switched to twisted pair wiring from the HU to the amps, the noise was gone. I installed an Audio Control Pre Amp Line Driver near the HU and that eliminated the noise problem with the EQX's in the system. The Pre Amp isolated the signal ground from the car and sent a balanced signal back to the EQX's. In my case, the noise was a combination of ground loop and radiated noise.

I am starting to ramble here. Bottom line is that alternator noise comes from three possible problems:

1. Noise on the power line.
2. Noise due to ground of the HU being at different level than ground on the processor and amplifier.
3. Noise coupling into your wiring that runs from the HU to the signal processor.

You have to systematically attack all three to have any success. I hope some of this is helpful.


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## NOFATTYS (Jan 5, 2009)

mda185...awesome post. thanks for the indepth info


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## lbc240 (Mar 1, 2008)

I agree with everyone saying that you need to run a twisted pair from the HU to the bit1. Even high-level signal can pick up noise. Easiest way to do it would be to cut the ends off a cheap pair of twisted-pair rcas and run them between the HU and Bit1


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## mda185 (Dec 14, 2006)

I don't post a lot on this forum but I have been installing car stereos for personal use since 1975. I also picked up a degree in Electrical Engineering and spent a bit of my career testing jet engines and helicopter transmissions for the Navy. Some of what I learned in my car audio hobby proved to be very useful in my career such as troubleshooting noise problems. 

I hope you find a solution. That sucks that GM sold such a hot performance car with a flawed sound system that is difficult to upgrade.


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## VP Electricity (Apr 11, 2009)

matthewo said:


> the whine is even there a little with the cars factory with no audio modifications. .


That right there strongly suggests a power filter on the HU power line might be a good idea. (Either that or the HU has internal ground loops between sections... in which case you are pretty much hosed). 

I still think you should try an Iso Link... you can run speaker into it.


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## VP Electricity (Apr 11, 2009)

mda185 said:


> I also picked up a degree in Electrical Engineering and spent a bit of my career testing jet engines and helicopter transmissions for the Navy. Some of what I learned in my car audio hobby proved to be very useful in my career such as troubleshooting noise problems.


Yeah, funny how that works. Most EEs I've met have no idea what causes noise in the real world...


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## matthewo (Jan 31, 2008)

thanks for all your ideas, i will get out and try them soon, just been busy, and the good thing is the alt whine isnt exteremly bad, so even any improvement from here would be great, and probably livable...


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## jmerick (Nov 12, 2008)

NOFATTYS said:


> oh sorry...PMP = portable media player. I am using a Cowon S9 and blue jean cable's 1/8" to rca cable directly into my Audiocontrol DQL8.
> 
> The Cowon S9 has a sweet radio built in as well. I sat in my car before terminating the stereo signal to the speakers and listened to the car radio transmission vs the Cowon Radio Transmission. The cowon surprisingly played all the local stations without a hit of static. the only station it had trouble picking up was hot 97.1 which is a rap station based in manhattan and im 70 miles away, so im happy with the results.


NOFATTYS - where did you mount the Cowon S9 in your G8?


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## NOFATTYS (Jan 5, 2009)

I bought a cell phone holder for 4 bucks on ebay and clipped it into the center stack vent hole. 

New Car Mount Phone Holder For Samsung/LG/Motorola/iPOD - eBay (item 270391656377 end time Jun-15-09 00:40:13 PDT)


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