This is the 10759th most frequent Korean word.
귀에는
"To the ear" or "in the ear."
In this sentence, '귀에는' refers to the ear as the receptor of the sound, emphasizing the auditory experience.
귀에는 소리가 선명했습니다.
The sound was clear to 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.