Literary / written register — common in fiction, poetry, and descriptive prose. In conversation, 音乐 (yīnyuè, 'music') or 音乐声 (yīnyuèshēng) is more typical. 乐声 specifically frames the music as ambient sound being heard, often from a distance.
mistakes
The character 乐 has two readings: yuè ('music') and lè ('happy'). 乐声 is yuèshēng ('music sound'), NOT lèshēng. Compare 音乐 (yīnyuè, 'music', yuè reading) vs 快乐 (kuàilè, 'happy', lè reading).
