This duo from Tuva ensures disbelief, when suddenly the woman sings a deep bass and the guy singing three octaves above. And what a bass! She uses the Tuvan undertone singin technique Kargyraa. It produces these deep tones with both the vestibular folds and the vocal cords. The man sings the famous Sygyt, the whistle throat singing style of the nomadic peoples around the Altai Mountains.