Board Thread:Naruto Discussions/@comment-35448581-20150520162940/@comment-2013124-20150523034150

Lightning, Echos, there are a few phenomena they could have studied. Orochimaru's grasp of sound was really developed. Dosu and Zaku were low level henchpeople and look at how he trained and equipped them. There's no way he doesn't know the speed of sound.