Mac external usb cd won't play on bluetooth speakers or headphones

When I play a CD through an external DVD drive attached to my iMac it works fine through the internal speakers but not through bluetooth connected devices.

I have a sound bar and the cd will play through that when connected via a jack plug, which in turn is connected through a USB socket to the DVD player itself, but when I switch to bluetooth connection it stops. The same happens when I try bluetooth headphones.

Music imported into the Music/iTunes app will play through bluetooth.

(Mac OS i Monteray 12.6.7)