When I ask Siri to play something from my music library it tells me it has to open my Audible app

Hello nowsthetime,

The way Siri works, most likely the first time Siri was requested to play something, it should have asked what app to use. If Audible was selected, Siri will continue to use it.

The good news is, Siri is a creature of habit.

If you request Siri play something using a particular app, then over time, Siri will assume you always want to use that app to play that type of media.

These tips on how to use Siri to play music can be found here, Use Siri to play music on iPhone - Apple Support:

• Play Apple Music: You can play any song, artist, album, playlist, or station. Say, for example, “Play ‘Gasoline’ by The Weeknd” or “Play Kehlani.” Siri can also play popular songs from different genres or years. Say “Play the top songs from 1990.” You can also play music on AirPlay 2-enabled devices in a specific room. Say something like “Play the latest album by Camila Cabello in the living room.”

• Let Apple Music be your personal DJ: Say something like “Play my Chill Mix” or “Play something I like.”

• Add music from Apple Music to your library: Say, for example, “Add ‘Evergreen’ by Omar Apollo to my library.” Or while playing something, say “Add this to my library.” (Apple Music subscription required. Not available with Apple Music Voice.)

• Add a song or album to a playlist: While playing a song, say something like “Add this song to my Workout playlist” or “Add this album to my Sunday Morning playlist.”

• Find out more about the current song: Say “What’s playing?”, “Who sings this song?”, or “Who is this song by?”

Tip: You can also identify a song playing on or near iPhone by adding the Music Recognition control to Control Center. Go to Settings  > Control Center, then tap  next to Music Recognition. With a song playing, open Control Center, then tap .

• Play songs based on their lyrics: Say “Play the song with the lyrics” and then say a key phrase from the lyrics.

Have a good day.