Slight pop noise from speakers after amp install

FitPilot · #1 (**permalink**) 10-21-2009, 01:35 PM

Has anyone else experienced a slight pop coming from the speakers after an amp was installed. I had a shop do it about 2 months ago and anytime I use the brakes I get a small popping sound. Is this a grounding issue?

MetalFit630 · #2 (**permalink**) 10-22-2009, 07:45 PM

Yes, it is a ground issue. That is really really not good. You run the chance of frying every electrical component in you car. And I can bet they would never consent to paying for repairs. They most likely did a crappy ground and it's looping through the brake's ground. Are you using the factory stereo? What size gauge wires did they use for the ground and battery? Where is your amp located?

You need to take it back there yesterday and have them fix it. If they tell you it's no big deal, run away very fast and find a shop that knows what they're doing.

FitPilot · #3 (**permalink**) 10-22-2009, 09:43 PM

Aftermarket Pioneer head unit. Amp is located in the hatch area on the pass. side. Not sure what gauge wire they used. I will take it in on Monday and have them take care of it. Where should they be grounding it?

Stravos · #4 (**permalink**) 10-23-2009, 12:04 AM

I just noticed this today on my system after reading this (and thinking "wow, I'm glad mine doesn't do that"). For me it's a barely audible snap, easily drowned out by the quietest music. I'm not familiar with how the break assist works in the Fit, but the snap happens long before any braking can be felt. I'm wondering if it's noise from the tail lights turning on, as they are likely grounded nearby.

I am running a Pioneer HU with Alpine amp in the spare tire well, grounded and powered with 4 gauge.

MetalFit630 · #5 (**permalink**) 10-23-2009, 04:00 AM

Yeah, that popping is bad. It is related to the brake lights turning on, and is one of the most common bad ground issue I've seen. It usually happens when the installer grounds to something other than the direct body of the car. The bad part is that it interferes with the electrical system of the car, in this situation the brake lights. It ends up making the brake lights see two ground, which can change the resistence in the circuit. Since resistance is not voltage, the problem will not be solved by a fuse popping. The problem gets worse because the ECUs work with very slight variations of resistance, and more grounds change resistance. So as a result, you can fry one ECU, all ECUs, or anything else. It ends up getting very messy, requiring a lot of time and money to figure out exactly what was damaged. I had a customer that had this problem from a smaller mom and pop shop, and it ended up costing over $3500 to get his 08 Camry repaired.

It also happens when someone removes one of the bolts in the front passenger or driver seat to ground an amp. This ends up messing with the airbag sensors in the car. I've heard stories (don't know if they're ACTUALLY true, though) of airbags blowing for no reason, with the dealer finding this as the problem.

They are SUPPOSED to be gounding only to the body. As in scratching the paint away to bare metal, checking under the car to make sure it's clear, and using non-rusting self tapping screws with star washers. Using three screws is best, making sure that the ground cable won't move. The ground is EXTREMELY important in any system in a car.

Once again, get it fixed fast. If they don't think it's a problem, go somewhere else. If you can't find someone to fix it, pull the fuse for the amp, then unscrew the ground cable for the amp, wherever they put it!

FitPilot · #6 (**permalink**) 10-23-2009, 02:23 PM

ok, I found the ground wire this morning. The shop did use 3 screws and the star washer. However the piece of "frame" if you want to call it that is a just in front of the right tail light, its a vertical piece that runs up and down and has a factory wiring harness running along it. It feels about as thick as a soda can, and the holes they made are a bit large for the screw so the ground is not tight. I will try different screws and see if that works.

Is this a proper place for the ground to be? It is metal just doesn't feel like there is a lot to it.

MetalFit630 · #7 (**permalink**) 10-26-2009, 06:58 PM

The brake light is probably grounding to that same peice of metal. It's best if you can ground it on the actual floor of the car. Just find a blank spot that won't be in the way of any panels and check under the car in the general area. If it's clear, use a flat blade screw driver to scrape away the paint until you have clean metal. Then use the three screws to fasten it tightly to the floor. You should be able to wiggle it around and play with it, and have it not move at all. Make sure you've pulled the fuse off of your battery cable first!

FitPilot · #8 (**permalink**) 10-27-2009, 01:31 AM

Well I took it back to the shop and they were very nice, re-did the ground. Alternator whine went away but the popping was still there. I guess the trouble shot it and it ended up being noise through the RCA's for the front speakers. They put in an inline filter and its all good now.

MetalFit630 · #9 (**permalink**) 10-27-2009, 10:55 PM

That's good. That's strange though, I would think it'd be the other way around. Alternator noise is usually eliminated with a filter, but the popping usually isn't as easy to fix. But that's what makes ICE so crazy, anything can happen!