Hello and welcome to Apple Support Communities, Alexis Spil.
If I understand your post correctly, you're experiencing sound quality issues within one app and sound works well with all other apps on your iPhone 8. I'd like to help.
Follow the steps in this article for the app with the sound issue:
If an app you installed unexpectedly quits, stops responding, or won’t open
Let us know if that resolves this issue for you.
Thanks for using the Apple Support Communities. Take care.
There’s a crackling sound when playing videos on YouTube,but only in the app..On desktop version,Everythings fine..sound is just fine generally on my iPhone 8 Plus..I’m running on iOS 11.1
1 reply
YouTube app issue