Roland VK-8M Owner's Manual page 22

Playing the Organ
The numbers (16', 5-1/3', etc.) printed on the knob of each harmonic bar indicate the
pitch of that bar in "feet." The pitch of each harmonic bar plays an important role in
creating the tone. The 8' pitch is the basic pitch of the sound, and the sound is created
based on this 8' pitch.
The pitches of the harmonic bars are related as follows.
fig.01-16
When the middle C (C4) note is pressed, each
harmonic bar will sound the following notes.
16' 5
one octave
below
22
1 / ' 8' 4' 2 2 / '
3 3
5th root 8th 12th
8' =
2' 1 3 / ' 1 1 / ' 1'
5 3
15th
17th 19th 22nd