I have always noted the Vibrate module sounded a bit "flimsy" or perhaps cheap. Because of that I always assumed I had one of the vibration modules that eveyrone is complaining about.
Last night I played a game on the phone that I hadnt in a while. "Max and the Magic Marker"
When you touch the screen to "Draw" with the magic marker in an illegal area it turns on the vibrate motor. What it seems to do though is toggle on and off VERY quickly while holding in one of those spots. The vibrate module sounded like it was flinging itself apart. It was far and away the worse thing I have heard coming out of my phone.
I decided to bite the bullet and go to the store and see about an exchange. I tried two demos and 3 of the employees phones and they all sounded exactly like mine with the diag test. I had also tried my wifes 900 and it sounded like mine in diag vibra test mode as well. They didnt have the game so I couldnt test that.
In the end I decided not to because I wanted to reconfigure a new phone so soon after buying this one about as much as I wanted to put a hole in my head and it seemed that there would be no difference.
So now I am wondering if mine is actually "normal" and there are worse sounding vibra modules because I find it hard to believe that mine is a "bad one" when others have taken their phones in and have found better units but I tried 6 that sound the same as mine.
As to what the problem is... My money is that part of the module is in contact with something that is transferring the vibration directly to the unibody thus causing teh resonance we are hearing.
HTC One X + 64GB AT&T
Asus Transformer Infinity TF700T
Asus Transformer Prime TF201 - Now in my daughtes hands
Former Devices: HTC One X 16GB, Nokia Lumia 900, Samsung Focus, Dell Venue Pro (for 2 weeks), Tilt 2, Fuze, Tilt, HP HX4700