Is there any chance to use my own mp3 files for lullabies or use an audiobook player?

You are free to use any mp3 files you like or any player. With the feature Turn off when sleping, just start the playback in your favorite player. Lullaby volume down will take care to bring to volume down after you fall asleep. For more details refer to Lullabies.

Tags: lullaby, audiobook