[Tig] OT: audio Highs speed different than Lows?

[Rob Lingelbach]

Here in Sao Paulo, a very dramatic summer thunderstorm is darkening  
the skies and animating the sky and air with CRRaaackkKKss and flashes.

I notice the CRRaaackkkKKs start out with high frequencies, then  
reverberate at the low end.  Is this only because of the directional  
nature of the difference in frequencies, or is it because the high  
end travels somewhat faster than the low end?  If the freq. range  
were fully simultaneous, I would think the high cracks would be  
synchronous with the low rumbles, at least for lightning that is  
directly overhead, as it is now.

--
A man has as many social selves as there are individuals who  
recognize him.
--William James
Rob Lingelbach   http://www.colorist.org