I'm having problems with alternator whine coming over my two front speakers. First, here's the technical part of what I have going on.

All four speakers are powerbass brand.
The factory head unit is being used.
I'm using an 8" sub under the rear seat.
The amp is a Kenwood Excelon 9000-5, and it's powering the four door speakers and the sub.
The truck is a 2011 Lariat SuperCab.

Okay, so as I said above, the whine is in the two front door speakers. It started after the Kenwood amp was installed. I had the truck back in to the shop that installed it, and they tried to put some sort of filter in the wiring to get rid of the whine. It didn't work. They told me that the only way to get rid of the whine was to replace the factory head unit with an aftermarket unit that would be able to handle the power of the amp. I had another shop look at it, and they actually tried swapping the amp in case there was a loose connection inside the first amp. This didn't work. I believe both shops are being honest with me, and the second shop said that the first shop had everything wired very well.

I'd like to keep the factory look and SYNC function, so I'm pretty sure that I need to keep the factory head unit. The problem is that the factory head unit is so weak. Does anybody have suggestions on what I could do? I'm almost to the point of having the shop remove the Kenwood amp and re-install the old single channel amp that was just powering the sub, and then running the door speakers off the head unit. I'll go with less power if it means I can get rid of that damn whine.

 

First shop doesn't know what they're talking about. The headunit isn't taking any power from the amp, so it's not going to affect the whine. Second shop was closer on by swapping it to see if the amp was defective. I'd start by checking all the grounds, making sure they're all clean and tight. Also make sure the first shop when they ran all the wires, didn't run any speaker or rca wires near the amp power wires.

 

Yeah I'm not a stereo person obviously. Maybe I should ask how the system works in the first place. By removing some trim panels, I can see that there are wires going from the amp to the back of the head unit. As it happens, one of these cables, the remote power cable, keeps disconnecting from the back of the amp because it's too thin. Now, how should I go about checking the grounds? Should I only be checking the fat ground cable? I apologize if what I'm asking is very broad. I'm an amateur.

 

Missed a couple things. The large diameter power and ground wires were run along the driver's side, whereas the other cables were run along the passenger side. The first shop did say something about the factory head unit not having additional preouts, whatever that means.

 

Let's start from the beginning, since you said its alternator whine, the whine increases with increased rpm's, correct?

Where is the amp grounding out too? Ground cable shouldn't be more than 2-3 feet at the most long.

What is the amp taking as inputs from the headunit? Is it rca's or is it a set of speaker wires?

Did they run the wires directly from the amp to the speakers, or did they run them back up to re-use the factory wires under the dash?

And to check the ground, unbolt it from where they have it, make sure the connection is nice and tight if they used a crimp lug, and then make sure where they bolted it is to bare metal.

 

Can you post up a picture of the where the amp is grounded?

 

Here's what I've learned over time....

The noise your describing sounds like ground loop noise. It can be caused from a number of things.
1. RCA cables near power or grounds cables.
2. Grounds should be less than 18 inches (if possible).If it's longer, use heavier gauge wire
3. Poorly shielded RCA cables. Quality wires are worth every penny!
4. Make sure the sound your hearing is actually alternator noise. If it's following patternes of when the truck is moving and if it changes at the shift points.... It's transmission noises. Newer vehicles have digital and computerized tranny's and they can cause noise as well. Usually it's because of cheap wiring. But it's always wise to keep everything as far as possible from transfer cases and transmissions.
5. If all that checks out...... Establish new grounds!
If moving wire, and making sure it's quality wire doesn't help. Try finding a new ground.
I had noises in my grand cherokee after an instal. The culprit was the grounds. They were chassis grounded trough the bench seat bolts. I took them off and bought gold plated receiver terminals, cleaned the metal area up with a steel brush drill bit and bolted the new terminals back down. Also put a dab of solder on the connection because I was being really ****!
Fired up the jeep, and I had crystal clear sound.

If all else fails, try using a ground loop isolator. The heavy duty ones get rid of all the impedance noise. Don't use the crummy little filters. They don't work.

Good hunting!

 

The amp is grounding out near the vehicle jack storage location. They have it grounded to what I'd call the body. There are two self-tapping screws going through the crimped-on terminal (I should really take a picture). The inputs are RCAs. Again, I'll really try to take a clear picture because that will show what I'm trying to say in much clearer terms. I really wish I knew if they spliced into the factory wires or if they ran directly from the amp to the speakers. I know that if the remote power cable disconnects from the amp, the radio will still show what song is playing, but no sound will come over the speakers. Maybe that's an indicator of how the speakers are wired??? Just a shot in the dark.

On the grounding issue... I'm thinking about relocating the ground cable. As you know, the vehicle jack mounts onto a plate that's bolted to the floor. I was thinking about using a wire brush to clear away the paint on one of these bolts, and then using it as the grounding point. You'll be able to see how they grounded it using two self-tapping screws, and I just don't think that's a good ground, even if that's not the cause of the whine.

 

STEVEO236... I'll have to listen if the pitch changes at shift points. I know that it varies in pitch while accelerating and decelerating. I'd say that it follows the RPMs. Thank you so much guys for being patient. I know it can be frustrating talking to an amateur like myself. I work on aircraft hydraulics, so radios are not my forte.

 

Alright guys. I attached two pictures. One shows the wiring coming out the back of the amp. The wires that come out of the white housing run along the passenger side, and up to the back of the head unit. The power cable (red), and ground (black) go alongside the driver's side. The ground terminates near the vehicle jack mount. The power cable continues along the driver's side and ends up connecting to the battery.

The other picture is of the grounding point. You can hopefully see how they used the two screws to mount the terminal to the body. The body is really thin at this point, and it appears to be bare metal. You might be able to see the bolt that secures the jack mount up from the current location. This is where I was thinking about moving the ground cable. I would just use that bolt after I strip away the paint. What do you guys think about that?

Trying to figure out how to attach these pictures....

 

Alright guys. I apparently can't post the pictures. I'll gladly email them if anyone wants to see.

 

I'd trying moving the ground, it's not gonna hurt anything if it doesn't work. As for pictures, try uploading to a site like photobucket, then copy and pasting the link it gives you that has the [IMG] tags around it.

 

I'm with pizzaman....

Try finding a new spot to ground the amp.

And I think I read something in your post about self tapping screws...????... If those are what they used to ground the amp,,,, that's deffinatly where id start!
Self tapping screws are NOT a good way to ground.

Also.... I'm doubtful that your jack holder is bolted to the frame of the truck. Try a seat bolt... Or a seatbelt bolt. Or any one of the stout heavy duty bolts in the truck. There's always a better ground.
If you have to lengthen the ground wire beyond 18 inches... Remember to enlarge the wire gauge.

No worries about asking questions man... Everybody is new at some point.
Hell,,, I ask dumb questions all the time! Lol!

I'll see if I can PM you with my email.

 

Watch this quick video on proper grounding technique

 

All good advice so far. I did relocate the ground. On my truck, there is a large bolt that holds the rear seat down. It's on the driver's side. I cleaned off all the paint on the bolt and the surface where the bolt tightens down. I used a multimeter to measure the resistance, and wound up around 1 ohm. I'm not sure if that's good for a truck, but I do know that it's good on a helicopter so I just assumed. Hooked everything back up, and the noise is still there.

The original installer said that the problem probably can't be fixed without an aftermarket head unit. I don't want to do that. Has anybody else heard of this? I guess I just figured that people used the stock head unit in many cases and didn't have these problems. The noise is only coming from the front speakers. Why wouldn't it come from all four? Most of passengers have told me that it's not a big deal because the music drowns out the humming/whining unless I'm using my phone through SYNC. I can see where they're coming from, but the perfectionist in me has a hard time accepting that answer.