I've had the exact same issue for months and months now. Interestingly, I occasionally get little bits of crackling even when the simulator isn't running - just when I have a lot of processes like playing a youtube video along with having other tabs and apps open - so it seems to be something that happens with lots of processing going in general. And the crackling continues if I plug in my headphones, meaning it's not a speaker issue it's something deeper (as the terminal bandaid / temporary fixes other people have posted imply).