Speaker Static with AMP muddy sound

[Sandjob]

Installed a small amp using Kicker loc from kick speakers. Power wire to battery aux post and grounded directly to chassis. I have amplified the front Kick panel (JBL 6.5) and the dash (JBL 4") in series. As long as the car is "awake" I can hear Static from all front speakers-None in stock rears. When engine is running it seems there is a engine clicking sound that is compressor like. The gain on the amp on a scale of 1-10 would be barely 1. Apart from the static which may be ACM related-hope someone can tell me, the system with treble and bass to zero sounds muddy and distorted. I have tried 2 different amps and have been installing car and boat stereos at the amateur level for 30 years. Any help, clues, Forscan mods etc is appreciated. UPDATE: Brake pedal also adds unwanted noise. I know LED lights can be an issue but i believe my tail lights are standard non Led because I have a Base Bronco.

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[Rex21c]

How are both the amps being plugged into the bronco's system, is it low pass through aux cables or high pass through the speaker output. have not seen how the system is setup on the bronco yet.

May have 2 separate issues going on.

 

[Rex21c]

I've been installing car stereos for as long as I have been driving and tons of thoughts come to mind. Right off is typically your get noise if your ground is not good, bare metal ground is best. If the ground is shared with other devices it can pickup noises through that. if the amp is mounted close to any other electrical components that put off a EM field, computers and such. If the bottom of the amp is touching the medal of the chassis, that can act as a ground as well which is a poor connection and can cause issues. So make sure the feet on the amp are good.

Another good test is to power on the amp and disconnect the line in and see if you still have issues, if the stock setup didn't have issues, i'll bet the head unit is fine. if you still get whine then probably a grounding issue since the problem is replicated across 2 different amps.

Here's a good reference to look through. Not sure how similar the setup is from boats.
Car Audio Noise Suppression Guide — Diagnosing and Treating Noise Problems in Your Car Audio System (crutchfield.com)

As far as the sound quality, I don't have much without looking at the speakers. If they have built in caps or bass blockers, I'd double check to make sure the speaker wires are hooked up correctly. Sometimes it helps me to just wack the reset and start all over checking everything.

 

[Sandjob]

How are both the amps being plugged into the bronco's system, is it low pass through aux cables or high pass through the speaker output. have not seen how the system is setup on the bronco yet.

May have 2 separate issues going on.

They are hooked up with a Kicker LOC from speaker output. The amp is in a plastic tray and grounded directly to the chassis. I unplugged the rca to the amp and the noise quit. This is my second attempt. I removed everything last night, rerouted power opposite side to the RCAs. Still have static, some engine noise and a change of pitch when I apply the brake.

 

[Sandjob]

They are hooked up with a Kicker LOC from speaker output. The amp is in a plastic tray and grounded directly to the chassis. I unplugged the rca to the amp and the noise quit. This is my second attempt. I removed everything last night, rerouted power opposite side to the RCAs. Still have static, some engine noise and a change of pitch when I apply the brake.

I am going to attempt a new ground tonight and possibly a second set of RCA cables run over the seats to see if they are picking something up. Thanks for your suggestions.

 

[Rex21c]

wow, I wonder if the LOC on the stock head unit are just not good.

 

[Mattwings]

I would also suggest you run a wire to the chassis ground near the battery (will eventually have to be the same gauge as the positive wire to the battery) and eliminate the current ground. You can pick up noise between grounds. I am unsure which components are steel and which are aluminum (maybe only certain body panels are aluminum?) but it will not work well as a grounding point if other components even share a connection or are bonded to aluminum.

You may also want to move the loc mounting towards the amp (high level signals are less susceptible to radiated noise). Also ground the loc (if it has a ground) to the same location as the amp, preferably at the chassis/battery ground point. You need to make sure any ground wire is the same gauge (for the same length) as the power wire.

 

[Sandjob]

maybe the chassis portion I am grounded to is aluminum. I have the amp installed in the rear jack tray and it is grounded under the amp tray directly to a chassis cross bar. I suppose I can try to snake a ground closer to the battery to test. I also have a backup NVX LOC I can try to swap out.

 

[BlueGhost]

Have you tried setting input sensitivity to low to show a higher load to the head unit?

 

[Mattwings]

I am getting everything put together to further upgrade my Bronco audio. I always run a ground wire from the main chassis ground when I run the amp wire, because it's such a pita if you get noise and have to chase down the issue and tear everything back apart. My experience has been it's much more often a ground loop than radiated noise. Sometimes you can even notice it by removing the RCA ground (in an extreme situation). In a very former life I was a 12V audio installer.

 

[Sandjob]

I suppose the input sensitivity is located on the loc as a gain? I am using the
Kicker 46KISLOC2
with no adjustment on gain, I believe it is pre-set . My amp is barely a click on positive gain, just enough to transmit sound.

 

[Sandjob]

I will run a ground to the main chassis point and see what it does, Not sure I have enough 8 gauge to reach.

 

[BlueGhost]

For some reason I thought you were using the Kicker Key LOC, guess I've read too many post about the key amps. I would try the other LOC, it sounds like its the LOC causing noise.

Are the amp and LOC grounds going to the same location? If not, that might held reduce noise.

 

[Sandjob]

The Loc is in front-was by the amp but I changed it around last night. It is on its own ground by the right kick speaker.

 

[Mattwings]

The Loc is in front-was by the amp but I changed it around last night. It is on its own ground by the right kick speaker.

Definitely at least run the ground from the loc to the amp. Gauge for testing doesn’t matter much, it just won’t pass as much current at higher volumes, but at low power you can just run a jumper and test it. Good luck, engine noise sucks

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