This is a problem that plagued me for some time. It was particularly bad when going over rumble strips like the last chicane on Catalunya however, I do believe I found the problem. At first I uninstalled the game. This seemed to work but it's not always ideal. After a while of terrible load times I decided to look for other solutions when I realised I had the master volume pumped up all the way to 20. Knowing that sometimes increasing a volume output of certain devices could lead to poor sound quality, I decided to set it back to the standard 10. Now? I can't hear any crackle with the game installed and with the bass boost on my headphones enabled (which leads to extra crackling!). So, if you get the dreaded crackle, should check if you have your master volume turned up.