When viewing through streaming apps, the sound plays through the Bluetooth speakers, but when using HDMI (Blu-ray player) sound plays through the projector.
How can I get sound via Bluetooth in HDMI mode?
Nebula II Bluetooth with HDMI
I would contact Anker support for an answer, it may not be capable of performing that function, I’m not sure if it is or isn’t because I am not very knowledgeable about this device. If it can’t do it you may be able to use a bluetooth transmitter through the aux.
You would need a Bluetooth transmitter connected directly to your Blu-ray player and paired with a Bluetooth speaker otherwise the sound is just going to play from the projector. It does not have the ability to send over Bluetooth from the HDMI port sorry bud.
Have you checked the settings?