[veedubbin]

I just installed a Alpine PWD-X5 (5 channel amp/DSP/SUB) and some new speakers in a 2021 VW Tiguan. I get engine/alternator noise and I have been trying to figure it out and could use some help. The Alpine PWD-X5 has a full harness that goes to the head unit and has no RCAs. I have the power wire on the opposite side from the speaker wire and attached to the battery and the ground on the chassis. I tried to move the ground to the rear power socket and the noise was still present, but at a higher and steady pitch. What should my next steps be?

 

[bapayton]

Direct grounds to chassis can still be noisy. You can test to find less noisy grounding points but it's not a simple process.

Going back into my 1990's car audio memories........

Going to try and link a few things:

Autosound 2000- Art of Grounding, old school but physics don't change much over time
Autosound 2000- Alternator Whine
decent YouTube video on alternator whine
Amazon Noise Filter

I've used Ground Loop Isolation but those are normally RCA based.

 

[veedubbin]

Update: it's not the ground. The factory stereo is putting out a bad signal. I checked everything and tried a direct connection and a line out converter and had varying but poor results. The final test was using a spare battery to power the amp and continuing to get the noise. After that I used the Bluetooth dongle on the amp to play from my phone directly to the amp and the noise was gone. I have now removed the amp and sub and and going to finally go to a q5. This was the final nail for the Tiguan.

 

[bapayton]

So the signals from the head unit passed through to the converter and were still noisy? Could be many things, a faulty HU, unmatched input/output voltages, poor factory ground location, etc. I hate electrical gremlins and I'm not really good at diagnosing them!

Best of luck with the Q5