This ambient piece employs 3 steel guitar parts: a bass+drone, a two-note baritone figure, and a melody line. The accompaniment is a tabla drum loop and road noise. The video was created with Magic editor.

Inspired by the music of Steve Reich.
Here’s another ambient piece based on chording algorithm used in Tripolar Expedition.
This algorithmic piece picks random notes from the Bohlen-Pierce scale for a soothing ambient effect. There are 17 iterations, each dropping the highest note from the remaining list.
This short piece, titled “Providence”, contains overlapping Bohlen Pierce chords. Each note includes a harmony 439 cents (9/7) above and another 439 cents below. A pleasant effect with no real parallel in the 12-tone system.
These two pieces were retuned to Bohlen=Pierce with the Melodyne 5 Editor. The first is a jazz piece I wrote on guitar as a teenager, reimagined in Band-in-a-Box with a trombone as the lead instrument. I wonder if an actual trombonist could play these notes.
The second is a sound collage based on Dennis C. Lee’s “Psi-seX 1”. Running these somewhat random noises through a musical scale filter makes a rather pleasant effect, in my opinion.
Here’s one way to adapt a standard 12-tone keyboard to play Bohlen-Pierce music. Some of the black keys are not used because the BP scale has fewer accidentals. The actual pitch reassignments must be done in software somehow.
I usually tune my steel guitars to D6 with G bass (G B D F# A B D F#). The Bohlen-Pierce tuning below uses the same string gauges with a BP fretboard designed by Andy DePaule. I simply place the fretboard over the standard one and retune to play in BP.
If you use a Peterson Strobe HD tuner, you can install the BP tuning table from the “Uncategorized” list at petersontuners.com/sweeteners/shared. That’s a lot easier than eyeballing the cents numbers on a traditional electronic tuner.
BP note | 12 EDO Tuning |
H | F -39 |
G | Eb +14 |
F | C +22 |
Db | Ab -17 |
C | Gb +37 |
A | D -2 |
H | Bb -41 |
F | F +20 |
Here’s some ambient music played on it:
This Bohlen-Pierce arrangement of Terry Riley’s “In C” was realized on the musical hardware described in Rehearsal Room. It was performed by 13 identical algorithmic musicians known collectively as The Technical Academy. A characteristic feature of the ensemble is an indiscriminate fader controlled by a Markov chain on each voice. This is the third recording of the completed algorithm.
The notes of Terry Riley’s original score were remapped to Bohlen-Pierce notes in a slightly modified A Moll I mode; the B note would have mapped to BP’s J, but it was changed to Jb simply because Jb sounded better. Riley’s C D E F F# G A Bb B becomes A B C D E F G H Jb. The work is titled “Not In C” because it’s based on this different scale.
Source code written in Ruby can be viewed at github.com/b0blee/TechAcademy.
I really like that. Help me understand what is going on, if you don’t mind.
Hi Mike. There’s a little USB Midi gadget that connects my computer to the D-110. I take the Midi Thru output from there to the U-110. The audio from both synths goes into the mixer, and the Tape Out jacks run from there to the Zoom recorder.
Since pitch bend affects all of the notes in a channel, I can only play one Bohlen-Pierce note in each Midi channel. The U-110 is handling channels 1-6. The D-110 is handling channels 7-12, plus percussion on channel 15.
If you want to decipher exactly what’s going on musically, read the Ruby file rehearse.rb on the TechAcademy Github page. This isn’t really a composition – it’s just putting some repetitive phrases in each channel to test the underlying classes and the hardware.
Hi Bob,
Looks interesting. Do you remember the string gauges you used for this?
Might be a good idea to publish the drawing of the fretboard so others can print it out to try?
I’ll send you those files when I wake up a little more.
Is that lap steel a 24.25″ scale?
The lap steel I made my own fretboard for is a 22.5″ scale.
Best wishes,
Andy
My string gauges for this lap steel are .013 .015 .018 .020 .026 .034 .038 .050.
Yes, it is a 24.25″ scale.