Diagnosis
HDMI ARC (Audio Return Channel) on this model is finicky and has specific setup requirements. The most common failure point is the HDMI cable or the Sound Output setting.
How to Fix It
First, you must use the HDMI 2 (ARC) port. Ensure you're using a High-Speed HDMI cable that explicitly supports ARC/eARC. In the projector's menu, navigate to Settings > HDMI > HDMI Signal and set it to 'Enhanced' (not 'Standard'). Then go to Settings > Audio Output and set it to 'HDMI (ARC)'. Power cycle both the projector and soundbar.
If That Didn't Work
Your soundbar may not be fully ARC-compatible or requires a specific setting. On the soundbar, ensure its HDMI input is set to 'ARC' mode. Try a different, known-good High-Speed HDMI cable. As a workaround, use an optical audio cable from the projector's 3.5mm Audio Out port (with a mini-Toslink adapter) to the soundbar.
Heads Up
The 2350's ARC implementation can be buggy with some TV streaming sticks plugged into the projector. If you're using a Fire Stick or Roku, audio may need to route through the stick's remote, not ARC. Consider using the stick's voice remote to control soundbar volume instead.