Acoustic Archaeology
Watched and listened to an amazing show last night on the History Channel (Canada) about Acoustic Archaeology.
A good introduction to it "Early Rock" is found at Orkneyjar Archaeology News - Were some ancient sites designed to be acoustically, as well as visually, awe-inspiring? http://www.orkneyjar.com/archaeology/earlyrock.htm?
"These (ancient) sites contain passageways leading to large circular chambers, and have a resonant frequency (at which sounds naturally echo and reverberate) of about 110hz - the frequency of the male baritone, the second lowest singing voice. Standing waves, whereby sounds are reflected off walls and superimposed on to one another, and other acoustic curiosities, have been observed in these and other sites. Stone circles including Avebury and Stonehenge also appear to reflect sound in distinctive ways.
Archaeologists have suggested that chanting, singing and drumming at these sites would have produced reverberating echoes that might have been interpreted as voices of spirits or gods; they may also have induced physiological and psychological changes in people, adding to their potency as sites of spiritual importance."
Thousands of years ago - people may have been able to see sound waves: "Experiments in a replica of the Newgrange passage, at Princeton University, showed that if a site was smoky or misty, standing sound waves would become visible as they vibrated particles in the air."
Found it very interesting!