Haze.

Ok so a few days ago I decided to swap out my stock radio for an aftermarket. After removing the console, I noticed that the little round red alarm thing(idk what its called) was detached and not hooked up to anything..which I thought was odd...anyways, I thought I'd be able to use the same wiring harness from my old car but I couldn't, so I put the stock radio back in the way it was and plugged everything back up..

And when I turn the radio on to the "CD" player I noticed this hissing sound thats audible right before a song plays...what do you think is the cause of this? It was never like this before, and I also feel like the AFBS has been affected in some way because it doesn't sound as crisp and clear as before..

on a side note everything in the sound system is bone stock...help please!