Static noise from tweeters

Hello, I have a seat ibiza 2019.
I installed a 4channel amp and a sub.
Amp : alpine bbx-f1200
Sub : alpine sbg-1044br

I have like a static buzzing noise from the tweeters its not loud but i could hear it and it bothers me.
When I disconnect the rca’s from the amp it stopes, Ive tried to lower the gain but even when the gain is the lowest there’s still the sound it goes down but doesn’t disappear.
I tried to change rca cable’s and it was the same’ the power and rca cables are running through the opposite side of the car.
The amp is connected 2 channels for my front OEM speakers and 2 channels for my subwoofer.
I don’t know what could be the problem.

I would like help, Thanks alot!
I would bring it to a good car audio shop. There are so many variables with car audio (I used to be into it big time) that it is hard to diagnose a grounding problem without looking at the wiring.  
Get a ground loop eliminator and put it between the RCA end and where it goes into the amp. Problem solve. Now go get the gain set by someone with a Mead setup tool.. Save you time money and you'll learn what I learned 35 years ago, cars are hard and expensive to get right. BUT I manage NOW to keep it under a grand every time, because of GREAT low cost cool running class ds..

The Mead auto audio stuff is the bomb.. Must have for serious thumpers...