Alternator whine in speakers. Please help!

I installed a sound system in my truck back on the July 4th weekend and I'm still having problems with it. I'm getting bad alternator noise that sounds like a supercharger with the engine running. What I've installed is listed below and the problems I'm having as well as what I've done for troubleshooting.

Current Problem
When I turn on my truck I get alternator noise in all of my speakers. An increase in RPM's causes an increase in the pitch of the noise. It makes it sound kind of like a supercharger.

With the engine not running and the ignition in ACC then there is no noise. When I turn the ignition to ON with the engine still off then I get a hum in all of the speakers. The noise sounds like it changes just a little bit when I press the gas pedal but not very much. This noise does not increase with speaker volume nor does it increase with my fan being turned up and down. I've even tried disconnecting the plugs on the gas pedal and the fan and heater/ac control.

Upgrades
Headunit: Pioneer Premier DEH-P800PRS
Amp: Zed Audio Leviathan (900W/6 channel)
Front Component Speakers: Hybrid Audio C61-2
Rear Mid: Hybrid Audio C5
Sub: JL Audio 13TW5
Speaker Wire: Knukonceptz 12ga
Amp Wire: Stinger 4ga (Power and Ground)
RCAs: JL Audio

Now when I first installed all of this equipment, I DID NOT have any engine noise. It wasn't until after I started troubleshooting a speaker popping problem.

No I haven't tried a noise filter on the power line and I really don't want one because this is just a bandaid for a problem and I just want the problem fixed.

After I installed everything I had a loud pop in all of my speakers. I didn't know what it was and thought I may have a bad ground. I moved my amp ground and then tried and still had a pop so then I proceeded to move my head unit ground. I went to turn on my truck and as I did that, I still had the pop but then I also ended up getting an engine noise problem.

I decided to start troubleshooting by removing RCA's to see if I could isolate a speaker then I also tried to just remove the speaker wire from the amp and nothing got rid of the popping noise or the engine noise. So I decided to read resistance from the rcas to ground and found that the low output rcas were bad inside of the head unit. I took it to get repaired at a Pioneer repair shop. I got it back and I still had both problems. I then found out my amp had a bad circuit in it that was causing the popping noise and so I sent it back to be repaired for free. I got it back and the popping is gone but I still have engine noise.

I've removed RCA's. I've removed speaker wires. I've tried to move the grounds from the hu and amp to different locations. I've even tried to ground at the same location. I've tried to directly connect the headunit to the battery to see if that would work and all that did was make it worse. When I say it made it worse, I mean the noise got louder and it sounded like I started having plug noise. I've had the alternator tested to see if I had a bad diode in the alternator and that was good. I took my truck to Toyota and asked them to do a draw test on the truck and that was good(11milliamps).

I purchased a second set of RCA's because I thought I may have a problem with that. That didn't fix it. I tried moving my RCA's around and that didn't help. I purchased a hu through craigslist and sold it because I still had a noise problem.

So then I took my truck to the place who fixed my hu. They substituted a kenwood hu and they said the noise was worse so they told me it was my amp. I tested my amp by connecting an ipod with RCA to the input of the amp and I grounded the RCA of the ipod to the truck. There is no noise in any speaker which leads me to believe there is no problem with my amp.

I took it to another car audio shop in my area and the first thing they did was substitute a pioneer hu into my truck and they told me the noise went away. They didn't troubleshoot any further and they verified that the amp worked good.

I've taken my hu back to the repair facility about five times now and they've told me that they can't duplicate this problem on my hu. So from here, I don't know what to do. If there's something wrong in my truck then I need some help trying to troubleshoot it. I just purchased a brand new head unit which will be here tomorrow for me to test. If that doesn't work then I'd like some help. Any help would be greatly appreciated.

Thank you in advance for any advice and help you can suggest. I'm willing to try most anything now. I really don't want to put a filter on my system. I think this is just a bandaid for what's actually wrong. I just want the problem fixed. I think this is a fixable problem considering I didn't have engine noise when this all started.

Chris

 

i have the same noise comming from my alt. i dont hear it through my speakers or anything, but it does sound kinda like a super charger. it noticed it after my audio install also. im guessing its because im puttin to much strain on the alt?

 

Mine is definitely going through the speakers. I can hear it with the head unit on but when I shut the head unit off it goes away.

 

bad ground somewhere..

 

Yeah, it sounds like a ground problem. Your power wires should run on the opposite side of where you have your ground wires and RCA Jacks. The ground wire should also be as short as possible. Make sure your head unit is grounded as well. A noise suppressor is a temporary fix, but if you need one I'd go with PAC.

 

Shielded wiring?

 

So I got the new hu in today and I still have noise in the system.

I tried the Pioneer DEH-P9800BT.

I called the car audio place who told me my truck was good when they put their hu in and they said all they did was put in a new hu in and the noise went away. I'm wondering if I am having a bad ground although I'm not sure how I can tell if it's bad. I've tested from my points to the negative lead of the battery and I get less than an ohm of resistance. I actually get about .2-.3 ohms.

I'm wondering about the ground though because when I use the ipod then there is no noise but with the hu connected there is noise.

The thing that bugs me the most is that I didn't have this noise when I first started everything. It wasn't until I moved the ground from the factory harness to a different point on the truck. I've returned it to the factory I'm going to move the ground to the negative lead on the battery and see if that does anything tonight.

Is there a possibility the battery could be causing the problem? I've had the battery tested and they said it was good. Just a thought.

Does anyone have any suggestions about how I could possibly read out anything with an O-scope. I've been told if I read through the 12v lines into the hu then if I see an ac wave then it's definitely the power coming in. Is there anything else I could check using the O-scope or any other thoughts and ideas?

Thanks to all who have posted so far.

 

Make sure the area's you are using for ground are clean. Sand those area's down to the metal. Have you considered a ground block ? I ran my ground wire to the frame and then to myground block. I wouldn't run my ground off the battery.

 

I was just connecting to the battery to see if it would fix the noise. It didn't.

So I took my truck to a local car audio shop. They originally told me my hu was bad but I told them I got a new hu and I still had the problem so they looked at it again and they said that the noise was coming from my RCA's. I thought they were good but they replaced them with a set of Stinger RCA's that are shielded. When I first got in the truck I still heard a noise but they told me it was just hiss. After driving my truck around yesterday I realized that the noise is still there it is just a little quieter and higher pitched. Still very annoying.

They also told me my grounds were fine. I'm willing to try most anything though so keep sending suggestions because really don't want to put in a filter but they were telling me that if this didn't fix it that they think the next option may be to put a filter in the system...

Thanks again for everyone's suggestions.

 

This sounds like something very similar that happened to me years ago. I had a system in my Jeep Grand Cherokee, and it had this same never ending noise problem which I sadly didn't fix until about 2 days before I sold it. I had a pretty nice Pioneer H/U, which I wanted to keep when I sold my Jeep so I put in a cheapo Walmart brand cd deck. Amazingly enough, the noise was gone! Here's what I ended up doing to fix the noise when I later installed this Pioneer deck into another vehicle:

http://www.hondacivicforum.com/forum/showthread.php?t=75438

Follow the fix that guy performed on his Pioneer deck and see if that fixes it. It worked great for me and I never had any more noise with that deck!

 

You're an AE just get some quality wire and rewire the whole truck! Probably what I'd do.

...and if you strip any screws you have to drill them out yourself...haha I used to be an Airframer.

 

I would hate to have to deal with trying to find that myself.

I tend to think of everything as modules. If it's not the head unit, speakers, wires, connections, etc... that leaves the amplifier.

It looks like a fancy amp, but there's always the chance that it was defective. Class D for full range tends to make me nervous to begin with, but the Plexiglas cover really makes me wonder about RF noise entering the circuitry. Maybe you could borrow another amp and test that theory out. If you rule out the amp, I'd look at the alternator itself.

EDIT: Might be over my head after re-reading that. I'd still look at the amp. Don't take anyone's word for it. Everyone has different ears and standards for sound quality.

 

Alternator and Ignition noise is generated by the positive connection.
make the ground wire as short as possible and
look for a, ground loop isolator or 12 volt noise filter (around $10)
not hard to find at electronics store or online

you might want to check a little more in depth IMO

 

I had a similar problem it ended up being the radio antenna.

 

So I've tried unplugging the antenna and that did nothing. I've tried unplugging all of the coils. I've unplugged the maf sensors. I've tried checking the engine noise filter on the truck which I'm pretty sure is just a capacitor and although I'm not sure of the exact value I should've read for the capacitance, the part number looked like it had the number on it so I think I was right. I'm pretty sure it was .47 micro farads. I did it a while ago so I don't remember exactly what it was. I've tried pulling out fuses in the fuse box inside the truck and all I would do was turn the truck to the on position and see if I get noise. I did the same for all of these things. I get noise when I put the ignition in the on position. If I had noise there then I'd get noise when the truck is running.

The reason I don't think it's my amp is that I've actually sent it back to the manufacturer because it had a bad chip and they tested it after they replaced the chip and found nothing wrong with it. This is how I've tested the amp. With everything hooked up normally I took a wire and I shorted the ground of the RCA's to the truck ground or anywhere on the truck body. When I do this I get a lot of feedback. So then I disconnect the RCA's from the hu to the amp and I connect an ipod with an RCA out to the amp. I left the wire that turns on the amp from the hu so that I could turn on the amplifier with the hu. Then I started the truck again and there is no noise in each channel I plug into. Then I shorted the ground of the RCA's to the truck and I get absolutely no feedback. Before anyone asks, no I did not leave the amp on as I switch from one channel to the next and I also had the amp off when I pulled the RCAs out to plug the ipod in.

I'd like to try to pull other things to see what exactly is causing the noise but I don't want to screw something up. If anyone has done this or knows how to do this without screwing something up so I can figure out what the problem is then I think this may work the best. Would it be safer to unplug items instead of pulling fuses? I just don't want to fry my computer for something stupid.

Thanks for the info about the hu fix SilverTacoZack. I may try that later. I want to try a few more things first to try and locate the noise. If I can't find it then I may end up resorting to trying that out.

 

I'm going to repost this over in the Audio/Video Section and see if I can get a few more responses from some other members.

 

Let us know if you come up with a solution to the problem.

 

I'll definitely let everyone know. Thanks for the help and if there's anymore suggestions then post them and I'll try.

 

Here's the link to the other discussion if anyone wants to follow what anyone else has said or thinks of anymore information.

http://www.tacomaworld.com/forum/au...-whine-engine-noise-speakers-please-help.html