It was the drone chanters, mick/misophist; they were so pitch perfect and an octave apart, that they sounded like a machine-made sound. But real people they were, nevertheless.

Excellent chanting. But what really floored me is the resources these guys put together. Respect! Wow - I can see I'll be spending time poring over the website this Christmas.

Katlaughing, thanks for this link, you made my holidays!