Hey guys I know that’s an ancient and boring topic, but I’ve also done a bit of my homework and looked through all the topics, but still didn’t find my case so, to the facts: Car: Seat Ibiza 6L 1.4i HU: Original by Seat -> Alana by Grundig Level for Sub: Crunch MXB 1200i Sub: Crunch GroundPounder 12D4 Level for FS and RS: Pyle QA4400III FS and RS are still the originals of Seat and VW Hifonics PowerCap 1Farad 2 times 102 from battery to d Steps 2 times 102 Mass of steps at 2 mass stars in the rear the two chinchs are on the other side of the car are so far away from the supply lines of the steps… The problem: Not too loud, nevertheless annoying noises of the Lima or whatever^^ in the FS and RS (rotary-dependent whistle and servo surren over them Speaker [volume independent]) The radio can be it actually not, had it until yesterday at the speakers and there was no whistle to hear, I also sometimes a speaker running over the HU and the others over the stage that have whistled from the stage that is not from the radio. I also tried to ground the chinch mass, i.e. to hold cables to the chinch mass and to the stage, Surren was even louder… vlt. know you indeed advice and can help me be happy about every tip PS: and thank you that you have read up here ^^ gruß foksie