XBOX 360 HDMI Audio Trouble

After months of playing the 360 on the 55" Vizio LCD 120hz, the sound has "all of a sudden" become crackly. The XBOX is hooked up via HDMI. I have tried and know the following:

1. Use a different HDMI cable (didn't work)
2. Tried all of the 5 HDMI ports (didn't work)
3. Went back to component hookup (which worked)
4. The sound is crackly through the surround sound and/or TV
5. My blu-ray is hooked up w/ HDMI and still sounds great.

It is interesting to note that this issue began occuring at about the same time as the last update from Microsoft.

Any ideas CNET?

A million thanks!