Hi guys,

The voice on promo could be a variation (not a synth) of two suspects:

McAlister (Xander's profile on internet confirm: the actor has done some work with his voice on the carreer) or Partridge (not confirmed like Xander, but the tone is almost the same).

My first theory was on Partridge... But i don't know anymore. 

It's 50% / 50%. 

Forget about Berthram. He's just a distraction, like kirklands brothers and Smith.
Also forget about Haffner and Styles: they're dead, the DNA confirmed.