uChord Chord Generator




The uChord is a one to four note chord generator. It takes a decimal number as input and generates a one to four note chord and inversion based on the value of the number. The chord note values are output as a quad signal and a quad gate output that reflects which notes are currently active. There is also an output of the number of notes in the current chord which can be used to adjust the chord’s volume. The notes in the chord, the inversion and the number of notes are displayed. There is a utility module for creating the chord values and a quad envelope which accepts the quad gate and a quad audio signal and outputs both a quad audio signal and a mono signal. See the demo for usage. By sequencing through the numbers it is possible to play various chord progressions.



Input Signal Range Notes
chord%20input decimal integer encodes notes and inversion for chord

quad envelope

Input Signal Range Notes
audio%20input -1 to 1 audio quad signal from chord generator
envelope%20input 0-1 modulation quad envelope signal


Output Signal Range Notes
o%20output 1 per octave quad output with note values
gate%20output 0-1 gate quad gate output - active notes are 1, unused notes are 0

quad envelope

Output Signal Range Notes
audio%20output -1 to 1 audio there is both a quad and mono output

chord converter

Output Signal Range Notes
output decimal integer integer representing the chord and inversion - connect this to the input of the uChord to hear the chord.


chord converter

Control Function Notes
keyboard enter desired chord one to four notes
inversion%20knob select the desired chord inversion range is -7 to 8



Meter Displays Notes
note%20number number of notes in current chord
inversion%20number current inversion
keyboard%20display notes in current chord

quad envelope

Meter Displays Notes
envelope%20input signal present light

chord converter

Meter Displays Notes
chord%20number decimal equivalent of current chord and inversion
note%20number current inversion -7 to 8

Version History

Revision File Date Notes
1.2 uChord V1.2.audulus (130.5 KB) 05/19/2018 initial upload to new forum


Revision File Date Notes
1.2 uChord V1.2 demo .audulus (1.2 MB) 05/19/2018 initial upload to new forum


I need to use this one more often!


Well this made my day. Wow. I have been avoiding “music” for a while so that I deal with more sonic details. Now that I am dipping into some melodies, I need to slowly work through all these tools. I just wanted to share this in case I am using it wrong or of I could do anything better.

chord trials.audulus (340.6 KB)

  • Not sure I fully understand the envelope, as well as the mysterious blue O on the uChord module, which doesn’t look documented above.


The topmost output labeled o is the one per octave output. The one below it as well as the number to the left is the number of notes in the current chord. To use the quad envelope, attachment h the gate signal from the uChord to some type of ADSR and the output of the ADSR to the quad envelope e input. Attach the output of your VCO to the a input and use either the quad or mono output.


So it looks like I have multiple issues.

  1. The particular ADSR I am using is not as responsive to certain gates as other envelopes are.
  2. The gate signal coming out of uChord is a rare occurrence. It seems like maybe that is because I have multiplied the output from uTuring in order move the decimal and put it into a useful range for quantizing. Is there a better way I should approach this?
  3. Wondering what the purpose is of having a dedicated output for the number of notes in a current chord? Is it for dividing back down to a root note or something for melodies?
    chord trials 2.audulus (341.3 KB)


Sorry about that, my mistake. It’s been a while since I looked at this. The gate output of the uChord is really just intended to mute the unused notes. It stays high for all the notes that are sounding and low for notes that should be muted. The quad 1 per octave output will drive an oscillator which will always generate 4 notes. To play less than 4 you need to mute one or more notes which is what the the companion module is for. If you need some sort of note gate you should probably place it after the poly to mono conversion
uChord V1.2 copy.audulus (153.5 KB)


Here’s a better example. The uChord is feeding a sub-oscillator which is gated by the companion module. The mono output of the companion module is then modulated by an envelope generator. The output of the uChord is also fed to a uPegg arpeggiator and the up and down and down arpeggios are fed to 2 additional oscillators. The melody line is provided by a uTuring run through a uNison module driving another sub- oscillator and passed through a state variable filter. Take the Phaser out if the CPU load is too much.
minor riff V2.audulus (1.1 MB)


How is it that a single oscillator can produce chords? Just looking at the Akemie’s Castle manual which says that, “in all modes VCO A has the ability to produce up to 5 voice chords.” I would have thought that there had to be a dynamic interplay between several oscillators to get the overtones?

  • I guess with digital you can just run the relative calculations based on the position of the wave, which just outputs the resulting waveform instead?


Akemies’s Chorduroy Castle.audulus (734.2 KB)