This is the 10759th most frequent Korean word.
귀에는
"To the ear" or "in the ear."
Here, '귀에는' is used metaphorically to emphasize paying attention through listening.
그는 이야기할 때 귀에는 집중하지 않았어요.
When he was talking, he didn't pay attention with his ears.
'귀에는' is describing the familiarity of the song as experienced by the listener's ear.
귀에는 이 노래가 익숙하게 들렸어요.
To the ear, this song sounded familiar.
In this sentence, '귀에는' refers to the ear as the receptor of the sound, emphasizing the auditory experience.