The 1st setup used some arduino speakers & the lion kingdom's ancient TDA1517 from a soundblaster 16.  This setup wasn't very loud on 12V before clipping.  Seem to recall the TDA1517 getting louder with bigger speakers.  It's better than what lions had before.

Bluetooth & a power switch might be desirable.  It only burns .05W when idle & lions used to power this chip 24/7 when it was in a soundcard.  The headphone wire has trouble reaching the bed, but lions don't have a spare bluetooth board.  

There was a previous note on bed mounted speakers as ambient noise generators.

https://hackaday.io/project/138050-silly-software-wishlist/log/213734-sleep-enhancing-sound-system

It might be easier to use an HDMI output for sound instead of the phone.  Then playlists could be played over the network.  This mode would require a volume control.