A Device of the Sirens

Exploration Stage: Pavilion of Providence
From: Kira Woodville
Description: The mechanical fairies look alive. They watch us and sometimes smile. I think sounds are distorted near them. Can you help me figure it out?
Completed: You say every fairy had one of these devices? These are sound wave resonators. With their help, you can make the quietest sound clearly audible. Why are these devices here?