Engine feedback through speakers

[Zeus33rd]

I just bought and installed some new stuff in my '04 Nissan Frontier. Rockford Fosgate Punch 10 & ported box, Fosgate Punch 400.4 amp and an Infinity Reference 6.5" component set. Already had a Kenwood deck. The rear two channels on the amp are bridged to the sub, the front two run the components.

I'm getting rpm related engine feedback through the component set. It's not that loud, and doesn't affect the quality of the music, but at lower volume levels or certain songs, it drives me crazy. I have to turn the gain down on the front channels to a level where I can't hear the buzz, but then the front doesn't match the sub. I could turn the gain down for the sub to match, but that still doesn't fix the problem. I've been ****in with it all day trying to fix it. I've checked and moved ALL my grounds to different places. I've added new grounds from the battery to the engine block, body, and frame. Just bought a new battery a few days ago. Took it to Autozone to get the alt tested, it checked out fine. Power and ground wires for the amp are nowhere near the speaker & RCA cables. About the only other variable I can think of is the crossovers for the component set, but how could hey be involved? Is there a way I can test those without totally tearing the interior out of my truck again and running wires directly from the deck to the amp?

Arggggggggghhhhhhhhhhhhhhhhh!!!!!!!!

 

[TucsonK5]

Is the feedback on both channels (right and left) or only one? If it's only one you may have a bad RCA. You've already checked the other ideas I had.

 

[Zeus33rd]

It's on both channels. The RCA's are both brand new Rockford Fosgate brand cables. I guess I can go mess with the RCA cables anyways though. I never really checked them. Thanks for the reply.

 

[lectric80]

Also keep in mind that there is a noise suppressor in the alternator that won't affect charging. So the alt could test good, but still be the source of your noise. A couple things you could try is run a ground wire directly to the housing of the alt, this may eliminate the noise. The other thing is a noise suppressor, although I haven't had good luck with them.

 

[oakknight]

are all your gronds in the same location ? Is the ground on an unpainted surface?

 

[Zeus33rd]

Also keep in mind that there is a noise suppressor in the alternator that won't affect charging. So the alt could test good, but still be the source of your noise. A couple things you could try is run a ground wire directly to the housing of the alt, this may eliminate the noise. The other thing is a noise suppressor, although I haven't had good luck with them.

I'll try the ground to the alternator thing next. Not sure I like the idea of using a noise suppressor. I'd rather just fix the problem.

are all your gronds in the same location ? Is the ground on an unpainted surface?

Grounds are in different spots, all on bright, shiny new steel.

I haven't messed with it in a week or so. I've gotta go pull it all back apart to install a new Sirius reciever, I'll mess with it again when I do that.


I did find this article about noise prevention-
http://www.termpro.com/articles/noise.html

Pretty damn good article.

 

[Greg72]

Joe,

The noise is a ground loop.....basically it's an audible indication that you have a difference in ground potential between the various components.

If you consolidate your grounds from the deck and amp to the same spot on the chassis (not the negative battery post!) you will probably resolve the issue. If that doesn't work, then the problem is poor power supply isolation in one of the components.... a lot less likely that is the issue, though.

 

[Zeus33rd]

Thanks for the reply Greg. One of these days I'll rip it all apart again and rework it all. The Sirius stuff I ordered is still sitting in the boxes it came in.

 

[oakknight]

Thats where i was getting at with the multiple ground location questions.lol

 

[viperrgh2]

Try and stick with least amount of grounds as possible, when grounding to engine try and go with alternator bracket. Also re-do the decks ground. Is it just with ipod or everything? Sometimes an ipod/mp3player charger or charging type plug in will cause the problem...