Chord Organ is the newest alternative firmware for the Music Thing Radio Music eurorack sample module. Developed by the inventor of the Radio Music, Tom Whitwell, Chord Organ ditches the original functionality. Instead, the new module mode uses customizable chord shapes to harmonize up to 8 internal oscillators in 4 available wave shapes, each resembling a different organ. The new functions are so cool, that Music Thing is offering a new DIY kit with a Chord Organ panel.

The Chord Organ converts all of the existing panel and CV controls to perform completely different tasks. The “station” or sample select knob and CV input control chord type or quality, while the start knob and CV set chord root position (also acting as a transpose or tuning knob). The module does not use 1v/oct tuning, however it does internally quantize for musical results. The reset button switches between banks of sine, square, sawtooth and dirty pulsewidth wave shapes (with the pulsewidth shape tuned an octave lower than the others). The reset trigger input has been repurposed as a trigger output, sending a trigger everytime the chord quality or tuning changes. The trigger output can be extremely musical. In the intro and outro to the video, the trigger output is patched to a channel on Maths, which then modulates the cutoff frequency of a filter, creating a nice stabby effect on the sawtooth waveform.

One of the coolest things about this firmware is the chord customization that is possible by simply editing a text file on the microSD card. The text file can include up to 16 different chords, each with up to 8 different chord tones. Producer/sound designer (and friend of VCL) James Bernard posted a number of great chord combinations, which can easily be pasted into the CHORDORGAN.TXT file.

1 [0,4,7,12,0] Major
2 [4,7,12,16,-5] Major inv 1
3 [7,12,16,-5,0] Major inv 2
4 [-12,-8,-5,0,4] Major inv 3
5 [-8,-5,0,4,7] Major inv 4
6 [-5,0,4,7,12] Major inv 5
7 [0,4,7,11,0] Major 7th
8 [4,7,11,0,16] Major 7th inv 2
9 [7,11,0,16,19] Major 7th inv 3
10 [-12,-8,-5,-1,0] Major 7th inv 4
11 [-8,-5,-1,0,4] Major 7th inv 5
12 [-8,4,7,11,23] Major 7th no root
13 [0,0,0,0,0] Root
14 [-24,-12,0,12,24] organ
15 [-8,-5,4,7,16] Major no root
16 [-12,0,0,12,24] 2 up 1 down octaves

He also posted the chords used in Tommib by Squarepusher…

1 [0,3,-14,-19] 1st
2 [-2,2,-14,-19] 2nd
3 [-2,5,-14,19] 3rd
4 [-2,3,-14,-19] 4th
5 [2,-14-17] 5th
6 [-2,-14,-17] 6th
7 [2,-14-17] 7th
8 [2,5,-14,-17] 8th
9 [0,9,-14,-21] 9th
10 [3,7,-14,-21] 10th
11 [3,10,-14,-21] 11th
12 [3,12,-14,-21] 12th
13 [5,14,-14,-22] 13th
14 [5,9,-14,-22] 14th
15 [5,10,-14,-22] 15th
16 [0,3,5,-14,-22] 16th


How are you generating complex chord sequences in your system? Tell us about it in the comments!

Chord Organ Custom Eurorack Chord Generator

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