Hey samoaku,
We see that you're hearing a crackling noise when you connect your iPhone to a speaker, and we'd like to help!
Are you experiencing this on multiple speakers or just one speaker? Have you tested this issue on multiple speakers?
If it happens with one specific speaker, we recommend that you contact the manufacturer of that speaker to see if there's a solution.
If it happens with multiple speakers, try restarting your iPhone and make sure the device is up to date. Check out the articles below:
Restart your iPhone
Update your iPhone, iPad, or iPod touch
Let us know how it goes!
Best regards.