Re over-/undertones

BTW,

If you are as confused about the undertone series as I was years ago, you
may be interested in the following 'recipe' for creating an undertone
series.

Take any length vibration (let's say a 10 foot string).

Divide it equally into any number (Again, let's say 10 for convenience.)

Let one section vibrate and record the pitch. Then let 2 sections
vibrate. The second pitch will be an octave lower than the first. Then,
3 sections (the pitch will be a perfect twelfth lower than the original
pitch.) Then 4 sections (now a perfect 15th lower.) Record your pitches.

Voila!: an undertone series!

Joe Downing,
in Syracuse