Anna-Maria Hefele was born on a stormy night, from the unholy union of a Theremin and a bagpipe, and this mutant freak can sing two notes at once.
I’m being ridiculous of course, polyphonic singing has been around for quite some time, the Tuvan throat singing being the most famous example. But every kind of overtone singing I’ve heard has always sounded a bit limited and drone-y, with a single fundamental and its resultant overtone series. But this woman has taken it one important step further and uses different fundamental tones to broaden the scope of melody notes she can sing.
In case you’re more confused than anything else, I’ll give you an entry-level tutorial on harmonic overtones (because that’s as far as I ever got with it). Any given note played on an instrument has the fundamental pitch, which is the strongest and loudest note you hear, and then there is a series of harmonic overtones which are present in the sound that might be varying levels of volume. If you’ve ever plucked a harmonic node on a guitar, you’ve experienced isolating one harmonic which is always present in the fundamental, but is simply less prominent. So what Ms. Hefele is demonstrating for us here is isolating various harmonic overtones to use as her melody notes in relation to the fundamental notes.
Then she takes this concept and just goes HAM. Moving the fundamental and overtones in different directions? Check please.