How do I play sound through my product?

• If you are projecting from a computer or video device using an HDMI or USB connection, you do not need to connect a separate audio cable to hear sound.
  
  Note: Older Macs may not support audio over HDMI and a separate audio cable must be connected to obtain sound.
  
  Related references
  Connecting to a Computer for Sound
  Connecting to a Video Source for Sound