Your TCL SmartProjector can be used as a Bluetooth speaker after switching it from Projector Mode to Bluetooth Speaker Mode. Just follow these steps:
Go to Settings > Projector > Bluetooth Speaker Mode
Enable Bluetooth on your smartphone and select TCL SmartProjector.
Follow the on-screen instructions to complete the Bluetooth connection
If you want to stop Bluetooth Speaker Mode, press the BACK button for 2 seconds to change back to Projector Mode.