Bohlen-Pierce minus 1
Listen to
Bohl-en Roll
This post refers to my song “Bohl-en Roll”, a piece based on a
dodecatonic scale which repeats every 1901.955
cents (3/1 ratio).
In order to fit a BP scale into an octave of a
standard keyboard I chose to eliminate one of the
usual 13 steps of it and I based this decision on
the Bohlen-Pierce Scale Research
Paper by Elaine Walker (the
pattern of my scale is 0, 1, 2, 3, 4, 6, 7, 8, 9,
10, 11, 12, 13).
This arrangement makes it possible to play all but
one of the “diatonic” modes presented on the above
mentioned paper. The missing step is ratio 75/49
(736.93 cents) used only on the “Delta” mode. On my
ET version the missing step is 731.521 cents.
The top picture shows my pitch assignment arrangement
for the octave C3 - C4. An octave span on a regular
keyboard equals an octave plus a fifth (a twelfth)
pitch-wise. The regular BP pitch assignment, on a
standard keyboard, would be the one showed on the
bottom picture. A twelfth would span 13 keys from C3
to C#4 making everything, in my opinion, much more
difficult. My reasoning is that in 12tET tonal music
very seldom all twelve available pitches are used, so
that should “equally” apply to BP music.