I’m intrigued, but the idea of an audio track in a medieval codex is a stretch. Marginalia were ink, not speakers. Still, if you can find a real artifact—perhaps a palimpsest with a hidden layer of parchment that, when heated, reveals a faint inscription—then a puzzle could work. Just make sure the sound you layer doesn’t outshine the actual mystery. Remember, the best puzzles are those that feel earned, not just a gimmick.