Updated 10/26/2015
Looks as if the download link was bad so I went ahead and updated it. This solution still works in El Capitan. Keep in mind that I didn't create the tools I only figured out how to use them. Credit for the kext goes to andrejkw at macrumors. Your mileage may vary but this is the easiest solution I've found. It has worked for many others. Definitely worth a try.
1. Download package located here https://dl.dropboxusercontent.com/u/248599/HDMIAudio-1.0.dmg
2....
Clover HDMI audio for NVIDIA & AMD cards. Easy way.
Looks as if the download link was bad so I went ahead and updated it. This solution still works in El Capitan. Keep in mind that I didn't create the tools I only figured out how to use them. Credit for the kext goes to andrejkw at macrumors. Your mileage may vary but this is the easiest solution I've found. It has worked for many others. Definitely worth a try.
1. Download package located here https://dl.dropboxusercontent.com/u/248599/HDMIAudio-1.0.dmg
2....
Clover HDMI audio for NVIDIA & AMD cards. Easy way.