XBox 360 has no sound with HDMI cable

Solution 1:

I was able to find an answer to this question here. Basically, the HDMI handshake doesn't work correctly between some TVs and the Xbox. The TV tells the Xbox to only allow PC-like display options if it's set to auto-detect the display settings.

To fix this:

1. Open the options on the Xbox Main Screen
2. Right until you get to Settings
3. Select Console Settings → Display Discovery
4. Turn the auto display discovery to Off

It will ask you to reset your TV and Xbox, after which you should have sound.
You will also need to reset your display configuration (i.e. your resolution/HD settings).