Dangbei Mars Pro has two 5w speakers to provide surround sound as a Bluetooth Speaker, so you can turn the projector into the Bluetooth Mode. there are the steps:
First, short press the Power button on the remote control and it will appear a screen with turning off the projector or switch to Bluetooth mode, navigate to the Bluetooth mode, press OK, and then the projector light source will be turned off.
Now go to the Bluetooth settings on your phone, search for the Bluetooth name of Dangbei Mars Pro, pair them, and then you will be able to enjoy Bluetooth mode with Dangbei Mars Pro.