As someone who's keenly interested in sound... The issue with the recordings presented in that article is the device used to record them. Whatever was being used apparently didn't have the range of amplitude needed to "hear" all of the sounds and shockwaves. There's a lot of clipping, specially in the second one with the shelling. Clipping happens during recording when the device can't handle the sheer amount of sound it's trying to record. It hits a limit and clips the rest; almost sounds like static or wind noise.
jas