Evidently, they didn't always use their mics, though they were attached right to the camera. Just above the lens, like a gun barrel... see?

9 seconds sound clip from the Cannibal Holocaust movie soundboard.

You can hear this line at 00:52:09 in the Blu-ray version of the movie.

Quote context

[...]

- Good, that's were will put the interviews with the families. and the one in which you talk about your search for them.

- Go ahead Bill.

(Film reel)

- This first segment is silent.

(Film reel) (2)

- Evidently, they didn't always use their mics, though they were attached right to the camera. Just above the lens, like a gun barrel... see?

- Remember this is a very rough cut. Almost like watching rushes... a lot of this stuff will be thrown out in the actual editing.

- Here we are... there should be some sound coming in now. No, no, not yet. Here...

(Man laughing)

- We've been walking for six days in this marvelous inferno.

[...]