Roland Music ATELIER AT500 Owner's Manual page 56

Selecting and Playing Sounds
What's the feet?
"Feet" is a term that began as a measurement of the length of the pipes in
a pipe organ.
The pipes that produce the basic pitch (fundamental) for each note are
considered to be "8 feet" in length.
Therefore, a pipe producing a pitch one octave below that of the reference
of 8' (eight feet) would be 16'; for one octave above the reference, the
pipe would be 4', and to take the pitch up yet another octave it would be
shortened to 2'.
The pitches of the harmonic bars are related as follows.
When the middle C (C4) note is pressed, each
harmonic bar will sound the following notes.
16' 5 1 /
one octave 5th
below
On tonewheel organs, the high-pitched footage for a portion of the high
range, and the low-pitched footage for a portion of the low range are
"folded-back" in units of one octave.
Folding back the high-frequency portion prevents the high-frequency
sounds from being unpleasantly shrill, and folding back the low-frequency
portion prevents the sound from becoming "muddy."
On the ATELIER faithfully simulates this characteristic.
54
' 8' 4' 2 2 / '
3 3
root 8th 12th
8' =
2' 1 3 / ' 1 1 / ' 1'
5 3
15th
17th 19th 22nd