1 wk old iPhone, I sound far away to others / Fade in and out

I just got an iPhone 4 and it worked fine last week, but now when I call someone else they say I sound like I fade in and out, or sometimes just really far away. If I turn on the spearker phone I am clear again. Turning off spearker causes me to fade in and out and sound far away again. Someone called me on their landline and also said I sounded far away, so it is not a cell phone to cell phone issue.

I found this is being reported by alot of people: https://discussions.apple.com/thread/2498579?start=0&tstart=0

Does anyone know how to fix this? I can't make or receive calls at all. Tried a full reset, restore, etc. Some are suggesting it has to do with a ground wire on the noise reduction part of the mic?

Thanks!