The
volume buttons control any external speakers you connected to the
projector.
You must adjust the volume separately for each
connected input source.
Warning: Do
not start playback at a high volume. Sudden loud noises may cause
hearing loss. Always lower the volume before turning off the
projector. Gradually increase the volume after turning the
projector on.
Note: To
adjust the volume of a connected audio/video system, set the
HDMI Link setting to On and the Audio
Out Device setting to AV
System in the projector's Settings menu.