Symbolism, Imagery, Allegory
What's that you hear? Mysterious music pierces the air wherever Emily goes, and it's not a stray ice cream truck. It's the one mystery of Udolpho Em can't quite pinpoint, and perhaps the most convincing evidence of an otherworldly presence in the book.
Magical or Mundane?
When Em first hears the music shortly before her father's death, La Voisin has some conflicting explanations: he thinks it's "the music of angels," but the rest of his family thinks it must be "shepherds playing on pipes." And then Father Denis tells La Voisin that "music often came to houses where there was a dying person" (1.6.68).
Fair enough. St. Aubert is indeed dying when Em hears the music for the first time. But long afterwards, she hears it when no one's dying (we hope). Instead, it's a comforting reminder that her dad's still out there, watching over her. With all the scary stuff that goes down at Udolpho and Chateau-le-Blanc, Em doesn't really seem to mind the spooky ghost music.
In fact, she goes seeking it out. Em lingers in the woods at night, "listening, gazing, and unable to move" as the music draws closer to where she sits (4.5.22). Girl, get out of there! But even though Em faints at every minor shock, she has a real fascination with death. Is it really all that permanent? Em doesn't know, but the music symbolizes an otherworldly presence in her life.