iPhone audio distortion
I'm having a sound distortion problem when using my iPhone. I contacted Apple Support but could not explain the problem. Most noticeably, the sounds go up and down when using the keyboard. The attention awareness feature is turned off. I recorded it while deleting as it's most obvious when deleting messages. When using Whatsapp, the sound explodes when you receive a message. The volume goes up and down constantly while typing on the keyboard. I switched from iPhone 7. However, I am very sorry for this problem. What should I do? Can someone explain my problem? If you compare the two videos, the sound in one of the videos is constantly rising and falling. The other has a fixed volume.
https://www.youtube.com/watch?v=F9MaWr3p-Ww
iPhone 13, iOS 15