Cause commotion — how we use the headphones (3,2,3,4)
I believe the answer is:
set by the ears
I'm afraid I can't even guess how this answer relates to the clue.
Can you help me to learn more?
(Other definitions for set by the ears that I've seen before include "using personal stereo?" , "Be violently opposed" , "Radio with headphones" , "is to cause disagreement" , "Cause trouble" .)