Static And Alternator Noise

Rob M · October 14, 2008

I just installed the following into my crew cab....

Pioneer Premier 800BT head unit. (Not grounded through factory harness, chassis of headunit also grounded.)

Pioneer d1720c components, 6.75 woofer in front doors, tweeters in pillars.

Pioneer 3 way 6.5's in the rear doors.

Polk MOMO 12" sub in homemade fiberglass box behind rear seat. (Don't try this!)

Audiobahn 4004t 4-channel for door speakers.

Audiobahn 8002t 2-channel for sub.

Everything sounds GREAT, and the imaging of the front components is amazing! Now here's the problem.

I have a constant static coming from all four channels when the volume of the unit is up but there is little or no music being played.

For example, between songs or with the CD/MP3 player on pause. This static is not directly related to the volume at the headunit itself.

With the unit on and zero volume, there is no static. Anywhere from 2%-95% up on the volume control gives the same amount of static.

100% of the volume control does increase the static, but i expect that.

The alternator noise sounds as if it's coming from only the tweeter in the A pillars, and is present at all times EVEN WITH THE HEAD UNIT OFF!!!!!!!!

This is not affected by the volume of the headunit at all, and is always present. I noticed this with the headunit OUT of the truck,

no RCA wires in the truck, and nothing to power the amps on.

I have tested every component and every connection with no improvement. Biggest improvement so far has been the gain control on the 4 channel amp.

Not a huge difference and definately not the source of the problem. I'm not pushing the gain too far. I've used jumper wires to test the ground and power all over the place.

All the grounds are very close in ohms from grounding points to the battery negative. RCAs not near power wire.

Sorry for the longest post ever, PLEASE HELP, I'M STUMPED, AND STRESSED!!!!!!!!!!!!!!!!

stadt11 · October 14, 2008

Check all your grounds again (are they all on bare metal), also make sure your signal wires & power wires are on opposite side of your vehicle, don't run them on the same side.

thecraft · October 14, 2008

I have a constant static coming from all four channels when the volume of the unit is up but there is little or no music being played.
For example, between songs or with the CD/MP3 player on pause. This static is not directly related to the volume at the headunit itself.

With the unit on and zero volume, there is no static. Anywhere from 2%-95% up on the volume control gives the same amount of static.

100% of the volume control does increase the static, but i expect that.

That sounds like background noise, the new Pioneer models are particularly bad about it. I eventually returned my DEH-P6000UB because of the noise. Unfortunately, there's not much you can do about it.

http://community.crutchfield.com/forums/thread/20008.aspx

http://www.gm-trucks.com/forums/index.php?...st&p=553365

The alternator noise sounds as if it's coming from only the tweeter in the A pillars, and is present at all times EVEN WITH THE HEAD UNIT OFF!!!!!!!!
This is not affected by the volume of the headunit at all, and is always present. I noticed this with the headunit OUT of the truck,

no RCA wires in the truck, and nothing to power the amps on.

I have tested every component and every connection with no improvement. Biggest improvement so far has been the gain control on the 4 channel amp.

Not a huge difference and definately not the source of the problem. I'm not pushing the gain too far. I've used jumper wires to test the ground and power all over the place.

All the grounds are very close in ohms from grounding points to the battery negative. RCAs not near power wire.

Alternator noise as in it varies with the speed of the engine?

Zembonez · October 14, 2008

That sounds like background noise, the new Pioneer models are particularly bad about it. I eventually returned my DEH-P6000UB because of the noise. Unfortunately, there's not much you can do about it.

+1

The Pioneer stuff is mid-pack quality at best. Heavy on whiz bang features and light on quality has always been Pioneer's way. You might want to go with a higher end head unit. They do make some pretty darn good sounding separates. The Audiobahn amps don't have a lot of filtration either. (most don't) They require a really clean signal. Amps are slaves. They just amplify ANY signal input.

I bet a different head unit would make a world of difference.

dirtracer455 · October 15, 2008

I have a constant static coming from all four channels when the volume of the unit is up but there is little or no music being played.
For example, between songs or with the CD/MP3 player on pause. This static is not directly related to the volume at the headunit itself.

With the unit on and zero volume, there is no static. Anywhere from 2%-95% up on the volume control gives the same amount of static.

100% of the volume control does increase the static, but i expect that.

I had this exact same problem with a stereo that I put in my old Ford Ranger. I pinpointed the problem to be the filtration on the amp I was using. Rather than replacing the amp, I bought a device called a ground-loop isolator which you can pick up at radioshack or any audio store. You hook up this device in between where the RCA wires connect to the speaker amp.

You can also buy magnets that clamp around these same RCA wires to help eliminate the static/alt noise.

As someone mentioned before make sure your power/ground wires are ran on the opposite side of the RCA cords, as this can also make the sound worse.

Hope this helps!

Rob M · October 16, 2008

Thanks for the ideas guy!!

The grounds have all been checked and rechecked, all on bare metal, all tested for resistance back to the negative battery terminal.

The signal and power wires are no where near eachother, opposite sides of truck, and the signal wires are all twisted, and shielded.

The amps are silent with a muting plug connected and the remote turn on jumped from the battery to leave the headunit off.

Thunderstruck-

the treads you linked to sound exactly like the noise I am getting (the static).

Yes what i call alternator noise does increase with engine speed, and is not dependent on the volume of the head unit, if fact the headunit can be OFF.

I've read this is likely the crossovers for the components picking it up. I've got the crossovers stashed in the kick panels (bad area i've learned).

Anyone think a noise filter on the Headunit 12v constant would help? In my troubleshooting i have run a wire direct to battery for power and ground with NO change.

I understand Pioneer is not a top shelf brand, but I have used their products in three previous vehicles with NO problems. just sticing to what I know.

Zembonez · October 16, 2008

Anyone think a noise filter on the Headunit 12v constant would help? In my troubleshooting i have run a wire direct to battery for power and ground with NO change.

I understand Pioneer is not a top shelf brand, but I have used their products in three previous vehicles with NO problems. just sticing to what I know.

Sorry it came across like I was slamming the brand there. Looking back, the post sounded worse than I meant for it to. I don't dislike Pioneer equipment. In fact I have only run into issues with Pioneer head units when adding amps. I just meant that their noise filtering might not be 100% fool proof. It doesn't show up until you start running amps. The description you give makes it sound like some filtration might just solve (or at least diminish) the problem. I would start with the power leads on the head unit. Your amps should be designed with enough filtration on the power side... but you might need to go there if isolating the head unit doesn't solve it.

Let us know what you find.

thecraft · October 16, 2008

The grounds have all been checked and rechecked, all on bare metal, all tested for resistance back to the negative battery terminal.

JSYK, a little resistance to an ohmmeter can be ALOT to a high-power amplifier.

Yes what i call alternator noise does increase with engine speed, and is not dependent on the volume of the head unit, if fact the headunit can be OFF.
I've read this is likely the crossovers for the components picking it up. I've got the crossovers stashed in the kick panels (bad area i've learned).

I don't have my crossovers inside my kick panels, but they are mounted to them. No problems at all...

Anyone think a noise filter on the Headunit 12v constant would help? In my troubleshooting i have run a wire direct to battery for power and ground with NO change.

No, inline filters are just a band-aid. You need to find the cause for the noise.

thecraft · October 16, 2008

Also, try grounding a length of wire and then wrap it around the RCA shields. If that gets rid of most of the noise, it indicates that the internal pico-fuse inside your Pioneer has blown and needs to be replaced. Google "pioneer pico fuse" for more info.

Zembonez · October 17, 2008

No, inline filters are just a band-aid. You need to find the cause for the noise.

Technically this is true but there are a LOT of head units out there that are very prone to amplifying ignition signal noise. It usually only shows up when running high power amps (which naturally amplify ANYTHING in the signal stream) The only way to stop that is to replace the unit or try filtering the power... ONCE you make sure that all of the sources and grounds are rock solid.

Rob M · October 17, 2008

Thanks for the feedback guys.

I took no offense to the Pioneer comment, you pretty much summed up why i buy them, lots of content and what I thought was good quality.

Now I'm not so sure......

I agree with the filter being a bandaid, and agree the cause needs to be found.....but i can't. And I've tried. If the filter can help, I will be better off than now.

The pico fuse is good, I've read all about it when doing my research, and have done the wire wrap test. NO CHANGE!

I have tried every test I've have read about trying to track the cause down, and I have waaaayyyy too many hours into this system.

I actually just put the interior back in today. PICS