2011 Macbook Pro w/ MiniDisplayPort to HDMI, NO SOUND?

Two suggestions:

1. Make sure you are using a correct mDP to HDMI adapter with audio support. Not all adapters support audio.
2. Open the "Audio MIDI Setup" program in your Utilities folder. HDMI audio options will appear when the mDP is connected to an operative audio input device.

HDMI is frustrating indeed, it either works or it doesn't. Any component can prevent it from functioning. You might try temporarily disabling or uninstalling those other audio output options, to ensure nothing is hijacking your MBP's audio prior to the Thunderbolt port.

Don't forget to investigate the settings for your TV as well, to ensure it is not looking elsewhere for the audio signal.

This is the adapter I use:

Mini DisplayPort | Thunderbolt® to HDMI® Adapter w/ Audio Support

It just works.

Edit: I would not have thought the technique at the end of this post would work, but apparently it did for at least one person:

HDMI audio out with MacBook Pro (2011)

Try that too.

Message was edited by: John Galt

Try the SMC reset as well. Seems like voodoo for a problem like this, but it's harmless enough.