HP ep9012 Digital Projector - Manual (Page 25)

Setting up
User’s Guide 25
Connecting a sound system
A high-quality 2.1 sound system is built into the projector. No connections are
required when using the internal DVD player. If you connect an external video
source to the projector, you can also connect its audio output to the projector’s
audio input.
✎
If you want to listen to the audio in private, connect a stereo headphone to
the headphone output. This disables the built-in speakers.