During the run, the character makes a strange ringing. Sometimes it sounds with every step, sometimes less often. What is this sound in general, and why does it sound at different intervals? And is it possible to remove it?
Is it really the jingle of coins in the pockets of the protagonist of the game? 
Probably armor
denizens of cairn uses iron for currency. so its not surprising that everybody had that metallic jingle sound accompanying their every steps.