• Unplug any headphones or external speakers.

• On your Mac, choose Apple menu  > System Preferences, click Sound, then click Output. Make sure “Macbook Air/Pro Speakers"” is selected, the “Output volume” slider is not all the way to the left, and the Mute checkbox is not selected.

   

  

• Make sure the speakers are plugged into your Mac or display & confirm all the cabling is seated properly.

• On your Mac, choose Apple menu  > System Preferences, click Sound, then click Output & ensure your new audio output source is selected.

   

• If you’re trying to listen through speakers or headphones connected only to the USB port on your Mac or display, choose Apple menu > System Preferences, click Sound, then click Output. Make sure the external USB speakers are selected. Open System Information, click USB in the Hardware section of the sidebar, then make sure your speakers are listed. If they aren’t, try unplugging the speakers and then plugging them in again.

   

If your external speakers still aren’t working, check the instructions that came with your speakers.

• If you’re using your computer’s digital output port (not available on all computers), choose Apple menu  > System Preferences, click Sound, then click Output. Make sure Digital Output is selected in the output devices list.

   

• Make sure your computer is connected to a digital-ready receiver using an optical digital cable, and that your receiver is set up for digital input (see the information that came with your receiver).

• Try adjusting the volume on your receiver. You can’t use the computer’s volume controls to adjust the volume while using digital output.