Whinning noise through amp please help. i have checked my grounds for the amp and the radio and i

Question

i have checked my grounds for the amp and the radio and i still have this terrible whinning noise going through my car. it only does it with the car running of course. if i turn on the head lights it gets louder and if i turn up the volume it drowns it out of course. where could this be coming from or how can i fix this. I do not want to really buy the filters but i want to actually solve the problem. also at times I get this static and crackling noise through the speakers like a cable is loose. but there is none loose! all items are new and the amp gain is down. hopefully one of u really could help me! asap