Navrozashvele

Hi I am having issues with static noise on aux. Whenever I just start ignition it has static when I start engine noise gets worse and when I rev its worst. I just noticed this as I installed roadtop kit which uses audio with ami cable, was using bt before. What should I look for to diagnose this?

P.S without ami cable noise is still there but less loud.

CaliBenzDriver

Third party device introduces audio noise.

These modern cars are loaded with strong noise sources (injectors, Ignition coils, FuelPump, Engine Fan, Alternator,...).

Try to use grounded shielded coaxial cabling for signals and capacitors to cleanup the power supply of your roadtop audio unit.

Also experiment taping power at different locations hopefully less noisy.

Try to figure if your electric noise gets in the power or the audio then concentrate on that.

Navrozashvele

There is static without roadtop unit. When AMI cable unplugged, static is there just barely noticeable on low volume, on high it's really noticeable but once you plug in AMI it is way louder(roadtop amplifies sound, it's a setting, if you turn it down, static gets less noisy). Ami cable has 3 legs so I think it's audio part to map just AUX so I believe it's audio issue.

Navrozashvele

I also should add that static is only on AUX option. bt, cd etc works fine

CaliBenzDriver

Do you have a picture of this AMI 3 legged cable?

You're saying that's where the noise is being picked up. The input is always noisy ... correct?

> S'nR: signal noise ratio:
Can you set a higher audio level into this input ?
This way you don't use a higher volume setting to amplify (low audio + high noise).

You want (high audio + low noise)

Navrozashvele

Correct, AUX is noisy without anything plugged into it. I will post picture once I get to car.

About 2nd part. aux comes from roadtop unit which is feeding audio with setting amplifies audio to max(my current setting) to ami so I believe it will cause high audio with lower noise compared to if I dial down setting so I am doing it properly I assume. On the other note on max volume I can't stand static but if you turn on music you cant even hear static lol so like I can technically let it slide but I am perfectionist and will get at root of this issue 100%

By the way. Once you have time, can you please try switching to aux at max volume to see if you hear static too? you have '14 car so you should have NTG 4.7 unit too.
I believe my whole interrior is rebuilt and someone f'd up wiring I am almost certain

CaliBenzDriver

"Try switching to aux at max volume to see if you hear static too?"

How can you switch over to the Aux input???

There is an interface module in some of these cars, perhaps it's what introduces noise picked through unfiltered dirty 12v... or wire harness coupling travelling side-by-side ?

Navrozashvele

There is aux option in my unit at bottom. AUX is there but there is no actual aux port it is being adapted to AMI/MMi or whatever it's called

in my case that big square port is adapter to female 3.5mm so that I can plug in roadtop box output

Senecat

Noise is always a bad ground.

Boarderjosh10

What type of device are you plugging into AUX?, some GSM radios in phones can cause additional electrical whine when antenna is activated.

Have you tried replacing the MB aux adapter cable? Mine had a kink and caused noise

Navrozashvele

So from my observation whole car interrior is rebuild badly. Static noise somehow is really familiar how the fan of head unit sounds. I this is bad wiring -> bad ground. Everything hints to 3.5mm ground loop isolator or as they call it "filter" in my country. I will have it made and update with results.

Navrozashvele

It's short cable without kink. Static is there without plugging in anything so it's internal bad wiring caused by probably rebuilding interrior. I am plugging in roadtop carplay kit input.

Boarderjosh10

You might be able to reduce some of the noise using a ground loop isolator in the aux line. Sometimes can reduce the noise even if further up the circuit there is a bad ground.

Navrozashvele

If it works, it works, if it doesn't I dont really care much. I am going to be selling my car anyway and looking to buy E400 either sedan or coupe. Not worth repairing it from my end. Will probably pull this kit during sale so I can put it in next car.