So glad you yelled "ECHO" at the end, as the entire duration of the video I was wondering about the acoustics in there.,(reply>), I am the owner of several storm systems, underground rivers and culverts in estepona malaga spain that are over a kilometre long. i own 5, kilometre long culverts including the rio Monterroso culvert the largest culvert in the world.,(reply>), You can hear it when he's talking,(reply>), "Hey you guys!" would have been my choice but each to their own :P,(reply>), Yells Echo, echo is returned in Japanese. Dang they are good!,(reply>), Hah, I was waiting for him to do that.