03 Cavalier Audio System

One day, i was driving down the freeway listening to a CD and my audio system started making crazy and weird noises. It was very irritating noises from the speaker. So i took the CD out, it was still making noises, i turned the power off on the radio and it still made the noises. Then, i turned the engine off, It started to make this low pitch horrible noise. I took the keys out of the starter and opened the door and it still made the noise for another 30 seconds till it finally stopped. I know its not the speakers because the radio plays just fine. But, very rarely it will do the crazy noises. I have the cavalier stock CD player. I will might post a video of it on here in a few days. I hope someone can help me plz.:frown: