Throat singing clip and spectrogram

Here is a quick clip of me doing some throat singing. I sing an "oo" vowel at about 165 Hz (E below middle C), visible as the red bar along the bottom, then transition to a shape that emphasizes the eighth overtone of that fundamental, 8*165 Hz = 1320 Hz. So that's three octaves (2^3 = 8) higher, the E two above middle C, just out of my falsetto singing range. I then go up the harmonics, which you can see as steps of 165 Hz in the spectrogram, up to 1980 Hz (a high B), far outside my singing range.
It's a spectrogram (produced by Audacity) of me singing an 'oo' vowel at about 165 Hz (E below middle C). That's the red bar along the bottom. I then emphasize the 8th through 12th overtones, clearly visible as steps (of 165 Hz) from ~1320 Hz to ~1980 Hz. Interesting, too, is the 'singer's formant' around 3 kHz.

I wrote a little more here.165 Hz 'oo' and overtones 8-12 (spectrogram)

Interesting and unexpected, since I'd never heard of it, was the clearly defined "singer's formant". That's the red bar through the middle, a resonance at 3000 Hz, which must correspond to a resonating space somewhere in my throat that is about four and a half inches long. Also of note is the second formant of the "oo" sound at about 800 Hz, right where it should be.