Created on: May 4, 2013
Last updated: August 25, 2015
Please refer to this Apple support article regarding audio throughput via the mini DisplayPort:
These Apple computers supply both multi-channel audio and video signals both over Mini DisplayPort:
1No additional adapter is necessary if you are connecting directly to the HDMI port on these specific models.
These Apple computers supply only video signals over Mini DisplayPort:
The NewerTech Mini Displayport to HDMI adapter does carry video and sound when connected to a Mac that supports that feature. If your computer is successfully transmitting video to an HDMI-equipped HDTV, but the sound is still coming through your computer rather than the TV, please take the following steps:
1. Choose Apple > System Preferences
2. Click on the "Sound" category.
3. Click on the "Output" tab.
4. Select the HDMI output option.
This will tell the computer to send the audio through the Mini DisplayPort to HDMI adapter.