Hi! I have built a sound system in my car, using hertz mille pro 2-way front sett, with an audison apf 8.9bit dsp/amplifier. and a custom-built sub in the back with a monoblock.
So I have a problem, where my DSP picks up noise from somewhere, when a RCA cable is connected to the DSP, I get this kinda static noise in the tweeters, even when the RCA isn't connected to anything else than the DSP(when RCA is removed the noise stops). The noise follows the rpm of the car. I have checked the ground and the power drop from the battery in the front and from the power cabels in the back, and there is no drop in voltage. I have also tried a new audison apf 8.9bit and the problem is still there. And yeah I know if the gain/sensitivity is set to high u get static, but even when the gain is all the way down it is still there.
And yes I have grounded it properly, double and Trippel checked it.
I didn't have this problem with my old amplifier, but when I installed the DSP the problem came.
I have sound-treated the whole car with alu butyl, the floor, doors, and roof. So the only logical explanation I have for this problem would be that there where some kind of distortion in the dc coming to the amplifier so that when it converts to ac for the speakers there will be some noise, but I am no expert here so i don't know if this would be a thing. Or that the alubutyl acts like a faraday cage where all the signals in the car would be trapped and bounce around.
So if someone has a solution or something, I would appreciate that a lot.
I'm getting tired of this shit so I hope someone with a lot more experience has encountered this before.
