You might have already noticed that most of the thing does work once you upgrade your Mac system to OS X Lion except one small bug and that is sound. You may not be able to get sound output through HDMI when using my Kanex Mini DisplayPort to HDMI Adapter. It actually means if you try to connect your 11-inch MacBook Air to my 47-inch 1080p HDTV, your sound won’t work.
Apple’s support communities have already received a lot frustration in the form of threads from Lion upgraders who suddenly lost the ability to pump sound through their HTPCs.
Luckily, a workaround has been discovered to fix the issue and it is very simple. Here’s how to get HDMI sound back into Lion. The fix is quite simple but it will take few minutes to complete. Basically all you have to do is to reset your Mac’s PRAM and SMC.
Now i am going to guide you step by step on how to get your HDMI sound back under OS X Lion Using A Mini DisplayPort or Thunderbolt Adapter
Resetting your PRAM
1) Shut your Mac down completely.
2) Without pressing them, find the these keys(Command, Option, P and R) on your Mac’s keyboard. Just put your fingers over them but again don’t press them yet.
3) Turn on your computer.
4) Immediately after switching on your computer, Press “Command+Option+P+R” Keys. Make sure you do it before you see the gray boot up screen.
5) If you follow the procedure correctly then your Mac will restart and you will hear the startup sound a second time.
6) Release the keys.
Completing the above procedure successfully means your PRAM’s has been reset.
Resetting Your SMC
The instructions required for resetting SMS vary from one computer to another. However, Apple has prepared a great supporting document which explains how to reset the SMC on any Mac. You can choose the right options to reset your SMC
Once you are able to flush both the SMC and PRAM, give your Mac some time to boot properly. Now its time to Plug in your Mini DisplayPort or Thunderbolt to HDMI adapter and ensure that HDMI is selected as your Sound output in System Preferences. If you follow above mentioned procedure correctly then your sound should now hopefully be working through HDMI under OS X Lion.
If you want to get more information on Mac OS X Lion then visit our Mac OS X section.