Random knocking and thumping and thudding noises

Hello,

I am looking for help here since i can not for the life of me find the source of my problem. Any help, suggestions and input is appreciated. Using GPT to help explain btw if that matters.

I installed a Phoenix Gold ZDAP-VAG1 Plug & Play DSP/amp in my Seat Mii Electric (fully electric car), and ever since I’ve been getting these LOUD random popping/knocking/thudding sounds through the speakers. It almost sounds like someone knocking on the doors. Sometimes it is brutal, lots of popping and at one point a large BRRRR happened. Music keeps playing underneath when it happens, so it’s not a dropout, just pops on top.

Details: • Happens mostly the first few minutes after startup. • Doesn’t matter if music is playing or not. Once it happened at super low volume where I couldn’t even hear the music, but the pops were there. • Putting music on pause seems to stop it, same with disconnecting Bluetooth from the car. I’m not sure if it actually is a fix, or if i’ve just been lucky. But for now, this has worked as a temporary fix so i can drive the car. • Does not seem to be power draw-related, doesn’t happen on bass hits only etc. One time it happened right after work during a phone call. • DSP/amp power is direct from 12V battery, Ground Zero 10mm cable, included fuse on wire ~10–20 cm from battery. Ground wire is ~10–15 cm long, under the seat contacting flat sanded bare metal chassis, secured tight with existing bolt. I even sanded and tightened more after the issues, thought ground maybe messed with the «zero reference». Idk feels solid and tight. • Amp/Dsp wired into the head unit with the included plug and play harness.

•	turning down source volume (which i assume is gain) does not work, but possibly lowers the volume of popping? Could be random.

Of course, when i’m recording, there’s conveniently no popping so sorry for no video.