Ignition Growl In Sub

7991LXnSHO

wanna catch the space herp
10 Year Member
Sep 1, 2010
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Kearney, NE
So my other question is how to get the ignition growl out of my sub. I have a small amp, dual coil sub, a big wire power line from a distribution block, HEI style ignition, noise filters on the power lines that go the radio and the amp, and a good ground to the body for the amp in back and to a metal dash part for the radio.
 
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So my other question is how to get the ignition growl out of my sub. I have a small amp, dual coil sub, a big wire power line from a distribution block, HEI style ignition, noise filters on the power lines that go the radio and the amp, and a good ground to the body for the amp in back and to a metal dash part for the radio.
Dedicated ground from the sub amp to the battery?
 
It likely won't help much, if at all anyway. Long ground wires can pick up noise from the chassis as easily as anything else. A shielded ground wire may help unless you're picking up noise from elsewhere.

Using non-resistor type plugs will do it but that kind of uncommon these days and folks with non-r plugs are usually aware of it.

Are you using line level inputs to the amp or speaker level inputs? Are those inputs shielded? How far from the head unit is the amp located? Where is the power feed coming from?

A good description of your setup might help to diagnose.
 
I was worried I was too detailed. The free air woofer and amp are in the back deck. The amp is turned on and off by the power antenna lead that was not used. The RCA jacks from the head unit. A long RCA cable carries the line level signal to the amp. This car has a power block in the line that goes to the battery. Is that enough? Do I need to add what station the head unit is tuned to? :)
The amp's ground wire is the same gauge as the power lead, and it is overkill for the amp.

I have wondered if a monster big capacitor parallel to the amp would help or if it might leak power and drain my battery.
 
My plugs are resistor as are the ignition wires. The power cable is not shielded. I have not seen a low gauge shielded cable. The head unit is run off the factory power wire.
 
My plugs are resistor as are the ignition wires. The power cable is not shielded. I have not seen a low gauge shielded cable. The head unit is run off the factory power wire.
You may want to do some troubleshooting to isolate the source of the induced noise. You'll need some RCA plugs that short the input of the amp to eliminate the input lines as being the source of the problem. Plug a shorting plug into both the amp's inputs, start the car, and listen. If the noise is gone, you know that whatever feeds the amp or the wiring that feeds the amp is the problem. Next, plug the RCA cables back into the amp and disconnect them from whatever feeds them. Put shorting jacks on the RCA plugs you just disconnected and start the car. No noise now, you know the RCA cabling is good. That shrinks down the number of things you have as suspects for causing the problem.

Radio Shack will have the RCA plugs and inline jacks you'll need to make the shorting test connectors. You'll need two of each to do the job. Just solder a wire from the center pin to the shell or solder lug for the shielding and you have the shorting test plugs and jacks.

See the Belden PDF booklet on shielding wiring at http://www.belden.com/resourcecenter/cablebasics/upload/shielding.pdf

See https://www.google.com/search?sourc...+sheilding&gs_l=hp....0.0.0.19782...........0. for more help on shielding braid

See eBay, www.digikey, www.newark.com or www.mouser.com for some flex braid sleeve that slides over your existing wiring.
 
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J,
I trust your EEC 4 advice fully. But the shorting plugs worry me. Shorting the amp's input will not harm the amp? I would never do this to the output, but had not thought about the input. Troubleshooting advice is what I needed.

I bet I have plenty of RCA connectors to do this. Thanks.
 
Nothing wrong with shorting inputs. J gave some pretty solid troubleshooting advice. It's actually common to short inputs that are not used. As you said, don't do it on the output though. The outputs are expecting a high impedance load, and by shorting them you will fry the outputs.

Are your RCA cables running adjacent the power feed for the amp? That could be a source of noise. Try keeping the RCA cables as far away as possible from any 12V wires.
 
Some good advice from above. In my experience, here are some guidelines to follow when it comes to noise in an audio system.

First is grounds. Grounds must be of proper gauge and the best place to ground to is the frame. Avoid grounding to thin sheet metal. When grounding to the frame, make sure to remove any paint, primer, corrosion, etc. at the grounding site. Use a proper grounding lug and/or star washers. I usually upgrade the factory grounds as well. Ground wires for external amps should be as short as possible.

As someone stated above, its a very good practice to run signal cables away from power wires. In almost all installs they usually must cross at least once, but they should do just that, cross. Running them parallel for any length can cause issues.

In my experience, I have found that noise filters, especially the cheap type, can cause more issues than they actually solve. If equipment is functioning properly and installed correctly, these should not be needed and avoided whenever possible.

I wouldn't waste time or money on a big capacitor. It's not going to help your issue here and even though you will find those that swear by them, their benefit to a system has failed to be proven notable in most recent years.

Even though the things above seem rather simple, they certainly do make a difference.

Best of luck and I hope this helps.