Watch a Woman Demonstrate Polyphonic Overtone Singing [VIDEO]

This will be one of the weirder things you hear today.

It's a woman showing off the technique of overtone singing, where the same person sings two notes at once. It sounds freaky, but it's real and no one has messed with the sound.

Her name is Anna-Maria Hefele, and she sings in an ensemble called Supersonus. It sounds like an electronic instrument, but that's her real voice.