alternator whine... speaker noise help? - Honda Prelude Forum

mikayls101 · 09-02-2011, 07:41 PM

hi everyone,

so to start i want to say i have a 2001 sh, for the sound system i have all rockford fosgate.. 2 1000 watt amps that power 2 12" subs and a 400 watt amp that powers the door and rear speakers. i have also a avic d3 deck. for a battery i am using a yellow top optima. so i have the power wire running down the drivers side of the car and i have the RCA and the remote turn on wire running down the passenger side of the car, for a ground i took a bolt off the chassis and ground it down to bare metal and attached it to that.. so when i turn my car on without starting it the sound system works perfect without any whining noise coming from the speakers but as soon as i start the car the noise begins. its a whining noise that gets higher pitched when i rev the car.. i have tried a few things and can not figure out how to get rid of this noise!!!! someone please help.

what i figured out so far.. when i take the RCA cables out of the 400 watt amp(the one that is hooked up to the door and rear speakers) the whining stops but as soon as they are plugged in the whining starts back up..

Kronn 98SH · 09-02-2011, 09:00 PM

Do you have another amp you could try in its place?

mikayls101 · 09-02-2011, 09:24 PM

unfortunatly no i do not...

Bongfloyd · 09-03-2011, 03:11 PM

I had that problem as well many years ago with a different kinds of cars and after all the troubleshooting and whatnot, I found out I had more than one ground grounding the system.

Make sure you run ONE heavy gauge wire to a good solid metal part of car and attach ALL your ground leads directly to this. Floating grounds can be a PITA and took me a long time to weed out. Make sure things like the radio chassis itself is not grounding to the metal mount in the dash (separate the points of the mount with hard rubber washers and make sure all your preamps/amps/crossover systems/etc are not screwed into metal as well and run them all electrically grounded to that one heavy gauge ground wire. That should do the trick as it helped me in the past

Bongfloyd · 09-03-2011, 03:19 PM

Oh and I forgot to mention, since it seems to be coming from the RCA cables (as you said you disconnect it gets quiet) and you also stated that you have a "remote turn on wire" running down same side as RCA cables, try removing that remote turn wiring away from the rca cables and see if that does the trick. ALL wiring for power should be on one side of car and all low level wiring (speaker wiring/RCA cables) should be on the other.

Also found this link on here that may help.
Noise Problems
Let us know how it turns out and we can go from there.

Cheers

mikayls101 · 09-04-2011, 07:19 AM

i seperated the RCA wires from the remote turn on wire and ran them down different sides and still have the noise.. also while im driving if i tap on the brakes or turn anything on you hear a lil click from the speakers and the noise gets a lil louder. so overall when the noise gets a little louder if i turn an electrical component on..

zfinatic · 09-04-2011, 08:16 AM

had the same problem in my civic when the plugs or wires were going bad. dont know if its the same with preludes but woth the check.

omega329 · 09-04-2011, 08:28 AM

Quote:

Originally Posted by mikayls101

i separated the RCA wires from the remote turn on wire and ran them down different sides and still have the noise.. also while im driving if i tap on the brakes or turn anything on you hear a lil click from the speakers and the noise gets a lil louder. so overall when the noise gets a little louder if i turn an electrical component on..

DISCLAIMER: I don't know anything electrical specific to a car.
This is just my first hand knowledge, not expertise.

My truck has similar problems. Here are some things to try.
Try getting an "RCA ground loop isolator".
Check and clean all of your ground points.
Buy thicker RCA cables.

Goodluck.

Bongfloyd · 09-04-2011, 10:41 AM

" My truck has similar problems. Here are some things to try.
Try getting an "RCA ground loop isolator".
Check and clean all of your ground points.
Buy thicker RCA cables.?

As to the ground loop isolator, I would save your money as I had mixed results at best. Again make sure ALL of your ground wires run to ONE central location and have ONE ground point not several as this will eliminate the small voltages above ground you have currently by having many ground points.

Joaquin Olivas · 02-03-2012, 01:17 PM

wrap uninsulated wire around the RCA outputs (HU, etc.) then do the same for the inputs on the amps. I did it and it was amps that caused the noise. Remember you wont completely get rid of it, you can only minimize it.

Re and Cheryl · 02-06-2012, 08:53 AM

You may also have an alternator going bad. To see if the problem is comming from the ignition or the alternator, remove the alternator belt and run the engine. If the noise is still there it is ignition related, if it is gone it is from the alternator. If the diodes in the alternator are starting to go it can cause this whine.

Re'

Rycon · 02-06-2012, 01:17 PM

What music source are you using? Make sure you are testing with a CD and not some AUX crap. Pretty much any AUX port causes whine and there is no way to get rid of it. Some stereos are better than others at minimizing the whine.

In my case, I noticed whine when any cables crossed over each other (RCA over Power or something). Soon as I kept them far apart, no whine.