Alright, during the song 'Kill the Noise (Part 1)' there's this really cool vocal effect just before the drop and during it. Here's the video (dubstep lyrics ftw)
It's the one at around 2:53, the one that just says 'Kill' in that really plasticine and synthetic sounding voice.
Also, in Black Magic/Kill the Noise Part 2), the choir at the beginning is singing 'Kill the Noise'. It's throughout the song too:
I just thought it'd be interesting to learn how he did that, I think it's unlikely he had access to a choir to sing for him. Maybe he did, I don't know. But I'm more interested in the first question.