Anna-Maria Hefele–graduate of the renowned Mozarteum Salzburg (Master of Arts)–is a multi-instrumentalist, singer and overtone singer and performs as a soloist worldwide with various ensembles, orchestras and choirs. She also performs widely in contemporary dance, circus and dance theater productions. In an effort to re-establish Western overtone singing in contemporary music, Anna-Maria collaborates with composers who write for this particular vocal technique. By filtering and amplifying the partials contained in the human voice, it is made to appear as if a person is singing two notes at once. Their viral YouTube video »polyphonic overtone singing,« now with over 19 million views, has been followed by many TV and radio appearances. »A voice like not of this world«, »The woman with two voices«, »Polyphonic vocalist achieves the impossible«–this and similar were the headlines about the exceptional musician.