Thank you Max. Yes I first came aware of these in earlier reports in 2005 and it still excites me. This could be the earliest evidence of overtone singing. The possibilities are awe inspiring. Thanks again

Thanks for the article. I wrote about the work of Iegor Resnikoff in my book Sacred Space-Sacred Sound: The Acoustic Mysteries of Holy Places (Quest Books, 2007). I sang in the prehistoric cave of Lascaux and had a very strong experience there. In 2007 I went to the Niaux cave and it is a phenominal acoustic site. Readers might also been interested in Paul Devereux's book Stone Age Soundtracks. A man named Steven Waller is also doing research in caves.