My take is that moving heavy rocks to deliberately create sound chambers seems unlikely but WKLB happens to be the right shape to be a stonking amplifier for low notes over long distances, maybe using drums and horns, something that might have been noted and utilised, if not considered disrespectful. The bodies have gone now so will the next visitor from here please take a ghetto blaster and see if it works?!?

As for crap apps at Stonehenge, headphones with the sound of the wind and some birds (which birds?) would surely be the most likely "original" experience.
As I said though, EH won't hand those out to visitors because traffic noise suits their current agenda. But they bloody should. A heritage guardian that suppresses the "authentic" - how crap is that?