I'm pretty sure most of the iPhone x will have the problem then not. I think people just don't use the iPhone at 100% like we do so most don't even notice it. it is 25% louder than the iPhone 7. Just break in the speakers, it does help.
This. The majority of iPhone owners likely wouldn't notice the crackling if they're iPhone volume was not maxed. Some of those that are noticing this, have their volume maxed at the full level and others who do not, likely will never noticed the crackling.