I have fixed this. Beleive it or not they have miswired the cable (from the Earforce Amp) end at the controller which houses a small cct board (inside the hockey puck) that controls the voice volume control.You need to reverse the Red and Black wire solder points(from the amp) so you will need some skill with soldering. I did this and tested the mic now works with the dial adjusting the voice vol.
Turle Beach needs to do a massive recall on these X1s; how can you realese a fairly expensive product like this that does not work out of the box. And they have removed all the forums from their web site concerning this as they know they have a faulty product,

You can buy a replacement on our web site. Here's the link:
http://www.turtlebeach.com/products/efx1/replacementparts.aspx

I just typed on google "Turtle Beach Ear Force x1 Replacement parts" There is a website where you can buy the cable puck for like 5 dollars plus shipping though.