I am trying to connect my macbook to an HD tv with an HDMI cable (cable is WITH audio), i plug it all in, go to 'audio' in system preferences to change the output location. However, the only thing that comes up is internal speakers. I have tried it on two different tv's with two different cables, and somebody else has used their mac with my cable and tv and it worked fine. But for some reason, my macbook wont give me the option to change audio output. How can i do this?? Whats going wrong? It is only the audio that is the problem, the picture is fine. Any help? PLEASE!?