With the included wired headphones, I often hear loud noise, a loud crackling, even my interlocutor can not understand me because of these sounds. The same thing happens with other headphones, but not when paired via Bluetooth. a loose contact or plug problems are eliminated, the problems are synonymous, without moving the cable. Someone an idea what causes these sounds? 

I've found that the glitches do not occur when mobile data is disabled. So the phone interferes with the wired headphone operation by receiving or sending mobile data. I do not think this can or will be fixed by an update. Looks like a design error.

Quick reply:
I haven't used the included earplugs, but my QKZ in-ear monitors does not pick up any noise. Could it be inefficient shielding of the cable?