note
If you connected the USB cable, you may not need a separate audio cable to amplify audio from your computer.
Amplifying Computer Audio
Your laptop probably has its own sound system; however, it may not be adequate for your presentation. If you need more volume or better sound quality, you can connect a stereo,
1.Connect one end of the audio cable to the Audio1 jack on the projector.
Audio1 jack
audio cable
2.Connect the other end of the audio cable to your laptop’s 
headphone jack or 
your computer manual if you’re not sure which jack to use.)
If you don’t need to make any other connections, you can plug in your projector and turn it on. See page 20 for instructions.
14Setting Up the Projector